AField Guide To Fermentation
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A FIELD GUIDE TO FERMENTATION A F I E L D G U I D E TO FERMENTATION by Arielle Johnson and Lars Williams This book belongs to A Field Guide to Fermentation 5 Introduction WHAT IS IN THIS BOOK AND HOW DO I USE IT? 7 Chapter One WHAT IS FERMENTATION AND WHY DO WE DO IT? 21 Chapter Two LACTO-FERMENTATION 31 Chapter Three KOMBUCHA 41 Chapter Four VINEGAR 53 Chapter Five KOJI 67 Chapter Six MISO AND SHOYU 79 Chapter Seven GARUM 87 Epilogue FERMENTATION.... 93 Appendix A CONTROL AND SAFETY WITH FERMENTATION 105 Appendix B THE TOOLS OF FERMENTATION 116 Glossary A field guide to fermentation All rights reserved © 2016 · noma Written by Arielle Johnson and Lars Williams Illustrations by Arielle Johnson Design by Tombola, Jan Rasmussen Printed by Dystan & Rosenberg Paper – Munken Pure 2 · noma a field guide to fermentation · 3 Introduction What is in this book and how do I use it? Each section of this book starts with the most basic practical information to do a fermentation for a noma recipe successfully. So if you only need to know exactly what to add to pumpkin juice to make pumpkin vinegar, or what the correct proportions of ingredients for a hazelnut miso are, that information comes first. If you want to understand why you need to add each ingredient, or what role each step plays in creating the final product, this information follows each basic recipe, in increasing depth and complexity. Besides learning some cool stuff, such as the fundamental reasons for specific salinity, temperature, alcohol, or humidity, you can also use this deeper background information to develop new fermentations, or figure out what processes are likely to work well with different ingredients. 4 · noma a field guide to fermentation · 5 Chapter One What is fermentation and why do we do it? 6 · noma a field guide to fermentation · 7 Fermentation is one of the many tools we use for preparing ingredients for the exhaustive coverage of fermentation in all its possible forms, or even every sin- menu at noma. You might be most familiar with fermentation as the process gle product fermented at noma, this book is rather an illustration of functional that creates alcohol in wine and beer, or that causes bread dough to rise, or that fermenting for flavor. makes kimchi or sauerkraut sour. It takes some know-how to transform raw ingredients and microbes from start At its most basic, fermentation is the transformation of food by various mi- to finish, and to cultivate the kinds of flavors we want to work with instead of croorganisms (bacteria, molds, and yeasts and fungi) and the enzymes they swampy, boozy, moldy, chemical-like, or rotten ones. One part of this is un- 1 produce. It is essential for the production of a wide range of foods and bever- derstanding what types of fermentations (and therefore, what general flavor ages, each with a distinct and varied flavor profile. Kimchi, wine, bread dough, profiles) are possible for a raw product, based on its basic makeup of proteins, vinegar, and soy sauce, while all tasting different, each owe their origin to the sugars, fats, starches, and water. The other part of this is understanding what action of microorganisms. temperature and humidity ranges, acidity, salt, sugar, alcohol, and oxygen levels or additions are necessary for creating a hospitable environment for par- Fermenting towards end-products as diverse as wine and kimchi, or squid ticular types of microbes to grow and ferment happily while excluding others. garum and creme fraiche, is a matter of starting with different ingredients, and working with different microbes. The microbes—across human cultures gen- The flavors produced by fermentation (see table) are diverse and often radi- erally, and at noma in particular—that we use for fermentation are yeasts and cally different from those of the ingredients we start with. Many of them are molds (both types of fungi) and acetic and lactic bacteria. produced directly from the fermenting microbes’ digestive processes. When these microbes extract energy from their surroundings, sugars are converted Why would you want to transform food with microbes in the first place? We do so to alcohols and acids and large, relatively flavorless molecules, like starches simply because it’s delicious. Throughout history, fermentation has been used for and proteins, are broken down into smaller pieces, which due to their new siz- several different purposes. It can preserve perishable foods—making sauerkraut es and shapes have different tastes and smells. from cabbage extends its usable life, for example. Fermentation can also make foods easier or safer to eat, removing cyanide from cassava and the historically indigestible Fermenting microbes have a lot of other metabolic processes that keep them sugar lactose from dairy products. Other microbes create intoxicating substances alive besides ‘eating’— they need to build and break down proteins, maintain such as alcohol. Finally, fermentation is often used for flavor—the purpose of cam- their cell membranes, and deal with shortages and surpluses of different ami- embert or sauternes is less about nutrition than deliciousness. no acids. The molecules they produce in doing these things (secondary metabolites) are often small,volatile, and have flavors, too: fruity, creamy, buttery, At noma, we ferment primarily for flavor. Rather than aiming for shelf-stabil- cheesy, winey, pickley, ferment-y, pungent, vinegary, bready, floral, sulfury, ity or specific health properties, the processes we use and the ways we use popcorny, rosy, vegetal, almondy, honeylike, leathery, haylike, spicy, and fatty them are directed by the flavors they produce. This enables us to better utilize flavors can all be created this way. Aging or heating fermented foods can lead to highly-flavored and short-seasoned ingredients. We can develop complex and further reactions between fermentation by-products creating other, different interesting flavors in commodity and waste products, like dried yellow peas flavors such as balsamic-y, burnt sugar, dried fruit, caramelized, toasty, choc- and squid trim. We can also create flavor profiles, like sourness and umami, olatey, malty, meaty, roasty, cheesy, and nutty. See the table below for more that are not widely-occurring in Nordic products. Rather than attempting an details on these flavors, molecules, and microbes responsible for them. 1 Per Sandor Katz, Godfather of the modern fermentation revival and MAD Symposium speaker in 2013 8 · noma a field guide to fermentation · 9 Flavor Example Compounds Type of microbe Type of fermentation Formation (if known) sour lactic acid lactic acid bacteria lacto-fermentation, miso sugars converted into lactic acid sour and pungent-smelling acetic acid acetic acid bacteria vinegar, miso ethyl alcohol converted into acetic acid sweet sugars- glucose especially Aspergillus oryzae koji starches broken down into indicidual units (sugar molecules) umami free glutamic acid Aspergillus oryzae miso, garum proteins broken down into individual units (amino acids, glutamic acid is one of these) fruity esters such as ethyl decanoate (generic fruity) or isoamyl acetate (banana-fruity) Yeast, acetic bacteria, lactic bacteria wine, beer, vinegar, miso an alcohol produced from fermentation (ethyl alcohol, isobutanol, isoamyl alcohol) binds chemically with a fatty/ organic acid (acetic acid, decanoic acid). Secondary metabolite related to cell growth and balances of oxygen, fatty acids, and other components that the cell takes-up nail polish remover ethyl acetate yeast, acetic acid bacteria vinegar, miso acetic acid reacts with ethyl alcohol to form ethyl acetate creamy acetoin lactic acid bacteria lacto-fermentation especially but not exclusively dairy byproduct of LAB consuming small amounts of citric acid for energy buttery diacetyl lactic acid bacteria lacto-fermentation especially but not exclusively dairy byproduct of LAB consuming small amounts of citric acid for energy cheesy (blue cheese) butyric acid Penicillium roquefortii + fat-degrading molds anything with fats whole fats broken down into free fatty acids (lipolysis) old cooking oil/paint aldhydes especially hexenal and nonenal oxidation rather than fermentation anything with fats whole fats broken down into fatty acids, then oxidatively degraded into aldehydes cheesy (parmesan) aldehydes, hexanoic acid, others yeast, lactic acid bacteria lactic & alcoholic fermentations winey "fusel" alcohols-butanol, isoamyl alcohol yeast, lactic acid bacteria lactic & alcoholic fermentations byproduct of yeasts breaking down amino acids as a nitrogen source pickley/ferment-y 4-hexenoic acid lactic acid bacteria lacto-fermentations fatty acid metabolism pungent/vinegary acetic acid acetic bacteria vinegar primary metabolite of acetic bacteria bready (several compounds) yeast alcoholic fermentations floral phenethyl alcohol yeast alcoholic fermentations metabolite of yeast breaking down amino acid phenylalanine sulfur hydrogen sulfide yeast alcoholic fermentations byproduct of yeasts synthesizing sulfur-containing amino acids popcorn/basmati rice 2-acetyl pyrroline lactic acid bacteria, Aspergillus oryzae lacto-fermentations & koji rose phenethyl alcohol, phenethyl acetate yeast alcoholic fermentations almondy benzaldehyde yeast alcoholic fermentations honey large esters and phenethyl esters yeast, possibly LAB alcoholic fermentations & lacto-fermentations leather phenolic compounds yeasts alcoholic fermentations esp at a higher temperature 10 · noma a field guide to fermentation · 11 Flavor Example Compounds Type of microbe Type of fermentation hay/barnyard 4-ethyl phenol Brettanomyces yeast spontaneous alcoholic fermentations spicy/smoky 4-vinyl guaiacol, 4-ethylguaiacol and other phenols yeasts spontaneous or warm-temperature alcoholic fermentations fatty & coconutty delta-decalactone and other lactones yeast, lactic acid bacteria alcoholic & lacto-fermentations Formation (if known) balsamic burnt sugar dried fruit caramelization toasty chocolate Maillard Reaction Products Aged products you started with koji free amino acids (broken down proteins) reacting with reducing sugars (broken down starch/carbohydrates) malt meat roasted cheesy nutty 12 · noma a field guide to fermentation · 13 14 · noma a field guide to fermentation · 15 Notes What microbes are we using? Most often, we're using lactic acid bacteria, acetic bacteria, molds, and yeasts (molds and yeast are both types of fungi). Fungi and bacteria are both microbes, but fungi aren't a type of bacteria and bacteria aren't a type of fungi. Therefore, in speaking about the fermentation process, using the term microbe, or microorganism, will be the most correct. So what is a bacteria and what is a fungus and when do I use them? Acetic and lactic acid bacteria are, obviously, both bacteria; yeasts and molds are both types of fungi. We use wild lactic acid bacteria for our lacto-fermentation, which converts sugars into sour-tasting lactic acid. We use acetic bacteria to convert alcohol into acetic acid to make vinegar. We use yeasts like Saccharomyces cerevisiae and Brettanomyces bruxellensis to convert sugars into alcohol. We use Aspergillus oryzae, a mold, for the enzymes it creates to break starches into sugars and proteins into amino acids. What is fermentation, please tell me in technical detail? In the strict biochemical sense, fermentation is a metabolic process where microbes convert sugars into another substance in the absence of oxygen. In a colloquial sense, fermentation is the transformation of food by microbes and the enzymes produced by those microbes. The difference, basically, is that lactic fermentations and alcoholic fermentations are true biochemical fermentations, because they involve microbes converting sugars into lactic acid or alcohol in a process that doesn't involve oxygen. Since growing Aspergillus oryzae on grains, converting wine into vinegar with acetic bacteria, or doing controlled proteolysis of beef with salt and koji for a few months to make beef garum do involve transformation of foods with microbes and their enzymes, we call them fermentations in our day-to-day conversations and in this book. 16 · noma a field guide to fermentation · 17 How did all of these fermentations develop at noma? cesses and failures led us to look into what was happening on a fundamental level—thus making the leap from merely considering the fermentations as in- Some time ago, we began to dedicate a significant amount of time to developing dividual products to using them as a set of tools with which to manipulate and our ‘toolbox’ of fermentations at noma to explore the flavor possibilities in our shape raw materials, as one would use a knife or saute pan. region. The garums began as a series of rather awful failures with mackerel and herPickling in vinegar developed early on as an important component of the noma ring. Oily, evil tasting 5 liter containers of salted fish oozing yellowish fat. Ob- larder— it is a simple way to reliably save the large amounts of plant products viously there was room for improvement— what could we change? The garum- available in the spring, summer, and autumn months for the cold and fairly bar- style ferment is an enzymatic one, carried out by the digestive juices of the ren winter. Elderflowers and berries, ramson buds, and hip roses are all excel- fish’s own stomach. The trials we had been doing with miso involved making lent pickled in vinegar, or heavily salted and then pickled in vinegar. The way a molded barley with Aspergillus orzyzae, which develops enzymes to break these flavors changed, grew, and ‘opened up’ during this preservation process down starches for a food source, but also produces enzymes to break down became an inspiration for investigating other types of fermentation processes proteins as a secondary metabolic process. In the case of miso, this is used to as a path to new flavors. Souring and ‘pickling,’ lacto-fermentation, growing break down the proteins in the soybeans to simpler amino acids, particular- koji mold, Pea-so, grasshopper garum and then meat garum gradually were in- ly glutamic acid. It occurred to us that this moldy barley could be the tool to corporated into the repertoire. better process the offcuts from fish. Within 10 weeks we had a far more tasty garum, dark and full flavored as a quality Nam Pla, which often takes a year The current fermentation program is a logical extension of preservation tech- or two to age properly. Unfortunately, the fats from these oily fish were still niques used extensively in Scandinavia for millennia. Salting, pickling, smok- present, and lent a distinct ‘harbour’ harshness to the garum, so it could not be ing, drying, and lye curing (a technique akin to nixtamalization), are all ancient qualified as a success. We were able to eventually remove the bulk of these via techniques for preserving food in this region, and fall into what we loosely ice filtering and centrifuging the solution, but we felt that the process itself was term ‘fermentation.’ The tremendous abundance during the summer needed to stronger than the particular product it had produced. be preserved in order to survive the long harsh winters. Lacto-fermentations of milk products, such as skyr, were an important protein source, although far In a sense, we had created a ‘tool’ of a recipe—a certain amount of molded bar- more critical were the sauerkraut type fermentations of vegetables as a source ley with its enzymatic properties to break down proteins, water to absorb the of necessary vitamins. flavor, and a certain amount of salt to limit the types of fermentations to one: enzymatic. All that was missing was a main ingredient to slot into our new Anyway, it was a small cognitive leap to apply the sauerkraut process to oth- ‘tool.’ At the time, the closest thing at hand (laughably, in retrospect) was a kilo er products like carrots, beets, and then every type of vegetable, fruit, mush- of grasshoppers, as we were, and still are, confounded and compelled by the rooms—more or less everything we could get our hands on, with various levels lack of insects in the Western diet. Into the blender they went, and into then of success. Some of this was inspired by research into other cultures, wheth- into the recipe ‘tool’ of barley, water, salt and temperature of 50°C. At the time er the process, such as the multitude of steps involved in making a Japanese we were using a second-hand heating blanket (like grandma had) and an old miso, or the product, such as the garum (salted fermented fish sauce) of Roman flamingo box, which René found hilarious, as he had never seen a heating blan- age. We began a series of trials with the ingredients around us, and the suc- ket before. Within 10 weeks, we had a rich, malt colored liquid with intense 18 · noma a field guide to fermentation · 19 soya-like umami, but also with touches of dark, almost Mexican mole-like fla- Chapter Two vors. We thought this one qualified as a success. From here on, we more or less stuffed every type of protein we could think of into our new ‘tool’—shellfish, chicken, pork, crustaceans, lean fish, liver, eggs, cod sperm, etc and etc. Most were okay, some were horrifying, but some were real successes. The offcuts of Lacto-fermentation squid, the bits and scrap that normally wound up in the bin, transformed into an unctuous jet black delight. Beef scraps formed an intense liquid with all the punch and nuances of a well hung rib eye steak. Salted and soured fruits, vegetables, mushrooms, grains, etc. The particular nascence of our garum, and the resulting development into the Process: product range which we now have and continue to expand, is emblematic of Sugars fermented into lactic acid by lactic acid bacteria, usually in a slightly salty and anaerobic environment how we strive to develop new techniques and foundations for the menu. A bit of inspiration from Ancient Greece, quick trials to get a feeling ‘in the fingers for the process’— followed by some childlike curiosity and child-labor-like Necessary components: hours of hard work culminated in a win. Raw produce, salt, vacuum bag Although we have now been incorporating these techniques into our menu for many years now, we still feel that we are merely scratching at the surface; that a depth of possibilities still waits to be discovered. 20 · noma a field guide to fermentation · 21 Basic Recipe: Lacto-fermented plums 1000g Red Plums, preferably organic 20g Fine Salt (no iodine) Weigh washed, cut in half, and seeded plums. Calculate 2% of the weight of the plums (so, 20g if you have 1 kilo of plums) and add that amount of fine, non-iodized salt to the plums. Gently combine the plums and salt so that the salt is very evenly distributed. Lay the salted plums neatly in one layer in a very large vacuum bag, so that there is adequate space left in the bag for the gas produced by the lacto-fermentation to expand. Seal in a vacuum sealer, removing all the air. IMPORTANT: Don't try to lacto-ferment with less than 1.5% salt, it will prob- ably turn yeasty or moldy and you'll have a bad time. Put the sealed bags in a secondary container (think cambro, not milk crate), in a room where they will stay at 25°C, and check the bags every day. When they swell up like balloons, open them and taste the fruit. When the fruit is ready, it will be somewhat salty, softer than when you started but not mushy or disintegrated, tangy, and have a somewhat pickled flavor. 22 · noma a field guide to fermentation · 23 Lacto-fermentation Notes able even after they’ve been frozen. More importantly, it creates a lot of nice flavors: a very pleasant tanginess, for one, and also a really special depth and Why a big vacuum bag? complexity. For instance, the Barley Koji is somewhat interesting on its own, Lacto-fermentation needs to be protected from oxygen, and produces a lot of nice smell, a bit sweet. But lacto-fermented, the Barley Koji is intensely fruity, carbon dioxide gas (which needs space to expand). the sweetness balanced by a complex sourness, a citrus fruit-white wine-noilly pratt reduction-tropical fruit, grain-broth lovechild. Why 2% salt? A salty environment inhibits the growth of most spoilage bacteria and yeasts, How do I know when it's ready? but lactic acid bacteria have a much higher tolerance to salt. This way, you're The level of “fermentedness” you’re aiming for will depend on what you’re suppressing the microbes you don't want and encouraging the ones you do. For fermenting and what you’re trying to use it for. For instance, if you are going to a while, we experimented with salt levels between 0.5% and 3% for ferment- ferment plums, the ideal starting point is a very ripe, yet still firm plum. When ing various ingredients and found that 3% salt tended to taste too salty, and finished the plum will be a bit softer, yet still maintain a desirable texture, and a that 1.5% and (especially) lower concentrations tended to let other microbial sweet/sour balance. Poor quality plums (say, which are a bit mealy and not that processes, like molding or yeasting, happen too often. 2% is a happy medium sweet) will fall apart into an average tasting sludge. If you are looking to fer- between salty flavor and controlling the fermentation. ment something like green gooseberries, the textures will be quite a bit firmer, both at the onset and completion of the process, and more care should be taken Why shake the bag? to balance the initial tartness of the berry with the eventual sourness. To make sure the salt coats all the fruit and mixes with the juices to make an evenly salty environment. What is happening here, microbiologically speaking? Lactic acid bacteria (LAB) are eating some of the sugar in the fruit and con- Why seal the bag under vacuum? verting it to lactic acid (which makes the fruit more acidic) and carbon dioxide Many spoilage bacteria need oxygen to grow; this prevents unwanted foreign (which makes the bag swell up). LAB are incredibly common in nature—they bacterial growth and also stops the fruit getting oxidized and browned. live on your skin, in the air, and on the surface of fruits and vegetables. Many of them have evolved to survive and grow in salty environments that would Why put the bags in a cambro? kill or inhibit most other microorganisms, including most spoilage bacteria/ It’s very possible that at least one bag will burst and leak. Since you put them in molds/yeasts. a cambro, you didn’t leave a mess for someone else to clean up. Over the course of a lacto-fermentation, different species of LAB will dominate Why ferment at 25°C ? the process. Lacto-fermentation is usually kicked off by Leuconostoc mesen- Colder temperatures will slow down the fermentation, while warmer tempera- teroides, which begin consuming sugars and produce lactic acid, acetic acid, tures can lead to spoilage or inferior flavor. carbon dioxide, and ethanol, as well as a smaller amount of a variety of flavorful compounds. Once L. mesenteroides has raised the acid concentration to about Why would I want to lacto-ferment something in the first place? 0.3%, Lactobacillus plantarum becomes the dominant fermenter, consuming Lacto-fermenting ingredients helps preserve them and makes them quite us- sugar and producing lactic acid to reach levels of 1.5-2%. If there is any sugar 24 · noma a field guide to fermentation · 25 left at this point, the fermentation is finished off by Lactobacillus brevis, which decays. Furthermore, the small amount of lacto-fermentation that occurs produces more lactic acid along with acetic acid and ethanol. This complexi- tends to break down the already extremely volatile and delicate compounds ty is why temperature curves are often used in lacto-fermentation, especially that we associate with ‘green’, ‘fresh’ or ‘grassy,’ which are often part of the with creme fraiche. Often the LAB is inoculated into cold cream, allowed to plant’s defense system, and once broken result in ‘swampy, moldy and more or come to room temperature for 24 or so hours and then cooled down in the less unbearably unpleasant.’ fridge- this changes the taste as some of the bacteria have their flavor profiles highlighted and others subdued. Lacto-fermentation Variations Lacto-fermentation Trouble-Shooting Lacto Berries Use a mixture of crushed and whole berries (crush half of them) so there's The fruit simply isn’t getting sour: more liquid fermenting around the fruit. Lactic fermentation is the conversion of sugars into lactic acids. If the fruit is not ripe enough, there is a lack of natural sugars, and the bacteria struggle to Lacto Ceps do their thing. Another possibility again originates in the fruit—if it has been Freeze and then thaw cep mushrooms in a vacuum bag and ferment them as sprayed with insecticides or fungicides, it is very possible that this is having an for fruit, above, with all the liquid they give off (use 2% of the weight of cep + adverse effect on the LAB, especially its ability to produce acid. As we do not liquid in salt). There will be quite a lot of juice at the end of the fermentation add a bacterial culture for inoculation, and depend on the wild strain native period. There are often multiple uses that come from the different aspects of on the surface of the item to be fermented, the ideal product is organic and the lactic fermentation. We often use the resulting liquid very differently than straight from the farm. Also check the salt you are using—there is some evi- solid matter being fermented. For instance, with lactic fermented ceps the liq- dence that the iodine often added may suppress bacterial growth. uid is excellent for adjusting the acidity of savory sauces, or simply spraying/ drizzling on vegetables or even seafood. The solid fermented ceps we may soak The fruit is moldy, or a white paste is seen, or a substantial boozy/wine flavor in birch syrup and dry into a chewy sweet/sour almost-candy. Or simply dry and odor is present: into a ‘leather’ that can be used as is, or cut into small intensely-flavored ac- This is most likely a salt problem. The amount of salt may have been incorrect. cents. Or added to something umami-rich like pea-so for a delicious paste. The bag may not have been shaken well enough to distribute the salt, leaving some parts of the product over salted, and some were left without protection Crème Fraîche from undesirable microbes. It is important to remember to lay the bags flat— Lacto-fermentation is responsible for the tangy flavor of cultured dairy (yo- the brine that results from the product losing water will protect it. If the bag is gurts, cheeses, creme fraiche, skyr, etc). It differs from plant product lacto-fer- standing in such a way that the liquid is unevenly dispersed, then the fermen- mentation in that dairy lacto-fermentation is usually inoculated with pure tation will be equally uneven. strains rather than spontaneously fermented, is not necessarily salted to start the fermentation, and involves different species of lactic bacteria more adapt- I tried a lactic fermentation of green plants and it tastes horrible: ed to metabolizing lactose (the primary sugar in milk). There’s often not a lot of sugar for the lactic bacteria to eat, and having prevented other microbes from entering the equation, the plant material simply 26 · noma a field guide to fermentation · 27 Cured/Lactofermented Meats Notes Lacto-fermentation is an important process for preservation and creating flavor in cured meats, especially sausages and others made from ground meats. Since whole-muscle cured meats like coppa or prosciutto start as essentially sterile on the inside, any microbial transformations happen on or close to the surface, and not throughout the whole muscle. Either by fermenting the small amounts of sugars naturally occurring in animal tissue, or the additional grains, sugars, or powdered milk incorporated into the mixture, lactic acid bacteria create preservative properties and the sourness in summer sausage, nduja, and others. Other incidental lacto-fermentations: Lacto-fermentation is an important step in making miso—the creation of acidity out of the sugar liberated from starches by the koji enzymes (if this sentence makes no sense, take a look at the koji and miso chapters) is important for both the flavor development and preservation of miso. This is a slower process in misos than in fruits or vegetables, generally, because misos have a higher salt content. Lactic acid bacteria are the main fermenter in water kefir grains (also called tibicos) and are also present, though not the most dominant fermenter, in kombucha. There exist lactic acid bacteria that happily live in alcoholic environments that play a role in the winemaking process, feeding either from the grape sugars or from citric and malic acid. These can play a desired role, softening the acidity of the wine, or can create strange properties like a “mousy” aroma or stringiness from ropy polysaccharides. 28 · noma a field guide to fermentation · 29 Notes Chapter Three Kombucha A slightly sweet, lightly acidic beverage Process: Flavorful sugar solution such as tea or juice fermented into acetic acid by a symbiotic colony of yeast and acetic bacteria Necessary components: Sweet liquid, kombucha mother/SCOBY, air 30 · noma a field guide to fermentation · 31 Basic Recipe: Herb Kombucha 1000g Filtered Water 5g Dried Tea or Herbs 120g Sugar 100g Previously Made Kombucha Kombucha Mother (SCOBY) Make a 12% (12 Brix when measured by a refractometer) syrup of water and white sugar (120g of sugar for every liter of water). Calculate 0.3-0.5% (3 to 5 grams per liter) by weight of the syrup and add that weight of dry herbs to the syrup. Heat together to 80°C to infuse for 5 minutes. Strain, cool, and add a kombucha mother, also called a pellicle or SCOBY, which looks like a floppy mat or jellyfish, and enough already-made kombucha to lower the pH to 5 (measured with a pH meter). This should be approximately 10% of the total liquid weight. Cover the mixture with a clean cloth (not a sealed lid) and let sit at 20-22°C for 7 to 10 days until the kombucha is acidic and slightly vinegary. The pH should be 3.7 by a pH meter. Unless for a specific use that requires it to be very acidic, use, refrigerate, or freeze before the kombucha is aggressively vinegary. Store the SCOBY that has formed in the kombucha in a container covered with more kombucha until you need to inoculate another batch. When the kombucha is ready it will be noticeably sour and have some vinegar aroma, with a bit of residual sweetness. If it is very sweet it is not finished yet; if the vinegariness is very irritating or pungent, it is over-fermented. 32 · noma a field guide to fermentation · 33 Kombucha Notes What if I want to store my SCOBY for a long time? You can also store the mother in the fridge, covered in kombucha. It will es- Why syrup? sentially go dormant and will require a few days in sweetened tea, at room The microbes that ferment the kombucha feed on sugar. temperature, with access to oxygen to get back up to speed when you want to use it again. Why herbs? Because you want it to taste like something, right? The herbs may be dried, like a How does kombucha fermentation work? tea, or fresh, like pineapple weed. Black tea is traditional, herb teas and juices will There are various species of yeasts and bacteria in the SCOBY that gets added also work. But the only requirement is that the product be flavorful and have the to the sweetened tea. The yeasts ferment the sugars in the tea into alcohol, and appropriate Brix. We have made a very sucessful infusion of the husks of black the bacteria consume the alcohol and produce acetic acid, converting a sweet garlic- delicious taste and the residual garlic paste provided enough sugar in itself. liquid into an acidic, slightly alcoholic one. The yeasts present include Saccharomyces and Zygosaccharomyces, and the bacteria include the acetic bacteria Why is it cooled after infusion? Acetobacter and Gluconacetobacter, and frequently include lactic acid bacteria If you add a starter to a hot liquid, the microbes will die. as well. Why start at pH 5? Why isn't this kombucha fizzy like other kombuchas you can get for drinking? Lower pH = more acid, which is inhospitable to mold, etc. Kombucha higher than Kombuchas that you buy commercially have usually been re-fermented in the pH 5 tends to get moldy. bottle; the yeast part of the fermentation produces carbon dioxide gas, which makes the drink fizzy if the container is sealed and the gas builds up. This kom- What the hell is a SCOBY? bucha recipe isn't directly intended for drinking as a fizzy beverage, but you Kombucha is fermented by a colony of yeasts and bacteria (kind of like sour- can make it into one by putting it in a closed container that can hold pressure dough). They form into a slimy mat as they grow, called a mother or a scoby. You (for example, clean old soda bottles) when it is still slightly sweet and letting it make kombucha by using a mother from a previous batch, and adding the whole re-ferment in the bottle. mat into a fresh batch of sweetened tea. What if I want to make Kombucha but don't have a SCOBY or mother? Okay, but why do they call it a SCOBY? The short answer is, you can't; you need kombucha to make kombucha. If you SCOBY is actually an acronym that stands for Symbiotic Colony Of Bacteria and have an unpasteurized, already-made kombucha, you can inoculate a new Yeasts. A SCOBY is usually found as multiple species of bacteria and yeasts bound batch of kombucha with that successfully, though it can be a somewhat slow- together in a slimy mat or biofilm of hydrocolloidal cellulose secreted by the mi- er fermentation process. If you have neither on hand, it's possible to order a crobes. SCOBY online. 34 · noma a field guide to fermentation · 35 Kombucha Trouble-Shooting Kombucha Variations There is a stringy jellyfish-looking translucent horrible thing floating in my Fresh herbs can be added to the sweetened tea + SCOBY for cold infusion to add kombucha: extra depth of flavor. Honey can be used as the sugar source—but since honey That is unfortunately what the SCOBY looks like. It shouldn’t be fuzzy, moldy, often harbors a wide range of wild yeasts and other microbes, you should boil black, or other strange colors though. the honey-kombucha base so the SCOBY microbes don't have to fight off other species to do their thing. The SCOBY looks fuzzy or moldy, or smells cheesy: It probably got infected with mold: If you can peel off the top layers of the Sco- Lemon Verbena Kombucha by and throw them away, the bottom part might be salvageable. To avoid this, Use lemon verbena or a mixture of lemon verbena and lemon thyme in the make sure the top of the SCOBY doesn’t get too dry (ladle a little kombucha above recipe. over it as it ferments), and make sure the liquid you’re making into kombucha is at least somewhat acidic (pH below 5) to stop molds from growing. Also, if Blackcurrant Leaf Kombucha there is not enough sugar, the Scoby can die, or not grow fast enough to com- Add dried blackcurrant leaves at 5 grams per liter (0.5%) to infuse in water at pete with the molds. 70°C for 25-30 minutes (sealed or covered in plastic wrap), strain, and then sugar added at 100 g/L (10%). Add kombucha mother and ferment, as above in The kombucha tastes like straight vinegar: basic recipe. (Blackcurrant leaves are not as aggressively flavorful as verbena When the kombucha scoby ferments, it is eating sugars and creating alcohol, and other herbs, and require a higher ratio and longer steeping time) then converting the alcohol to acid. If you let it go too long all the sugars will get converted into acid. You can’t really reverse this process but the kombucha Elderflower Syrup Kombucha is still OK to use to start a new batch. This is also a method for creating some- Adding a kombucha mother to elderflower syrup containing 30% sugar (30 thing rather close to a traditional vinegar, but much faster. Brix) will make a very sweet elderflower kombucha. Diluting this syrup to 15 brix makes for a lighter, more traditional-tasting, drier kombucha. Juice Kombucha Juices (carrot, apple) can be used to make juice kombucha. The carrots you use should be as sweet a variety as possible; check the brix of the juice and adjust if it is below 8-10 brix. Apple juice makes a very delicious kombucha. Rose Pulp Kombucha This is a Kombucha that we make from the left-over pulp from a rose oil production, which is simply wild beach roses blended with oil. Once the oil had been fully pressed out of the pulp, we mix that pulp with a 12% sugar solution, 36 · noma a field guide to fermentation · 37 allow it to steep overnight, strain the liquid (taking care to skim the oil) and use Notes that as a base for the Kombucha. Milk Kombucha Milk, with a good deal of care, can be used to make kombucha. It is critical to incorporate a sufficient amount of liquid mother in the form of a previous batch of kombucha, without lowering the pH too much. With some attention, it is possible for the kombucha to thicken the milk and lend a pleasant acidity. If the fermentation is allowed to continue for too long, the pH will drop too low, denaturing the proteins and splitting the milk. If the milk Kombucha spends only 2 days at 20°C and then put in the fridge, it’s possible to set it, like a fresh cheese. Kombucha Crème Fraîche 800g Milk 200g Cream 200g Kombucha- Elderflower Kombucha works very well for this. Incorporate the ingredients. Ferment at 20°C for one day, then place in the fridge to finish fermenting for two more days. 38 · noma a field guide to fermentation · 39 Notes Chapter Four Vinegar Sour liquid fermented from an alcoholic mixture Process: Ethyl alcohol fermented into acetic acid by acetic bacteria, with lots of oxygen Necessary components: Liquid, alcohol, vinegar starter, air 40 · noma a field guide to fermentation · 41 Basic Recipe: Single-Step Juice Vinegar 1000g Juice 200g Unpasteurized Vinegar 96g Ethanol Weigh the juice. Calculate 20% of this weight and add that amount of unpasteurized vinegar. Calculate 8% of the total weight you have ( juice + unpasteurized vinegar) and add that amount of high-proof (96%) ethanol. IMPORTANT: the alcohol you add MUST be food-grade. Everclear, overproof vodka or rum, or food-grade 96% ethanol are all fine. Anything labeled “100%” or “Denatured” will contain unsafe or poisonous substances. Perversely, “100% Ethanol” has had benzene or something else nasty added to it to de-water it and should therefore be avoided. It’s only possible to get 95-96% ethyl alcohol via distillation, so this is the highest possible purity you will be able to find that hasn’t definitely had something weird done to it. If it says that it has had isopropyl alcohol or methyl ethyl ketone or any other chemical name that’s not ethyl alcohol or water added to it, don’t use it for food. Ethyl alcohol for torches or stoves should NEVER be used to make vinegar. Put the mixture of juice, unpasteurized vinegar, and ethanol in a container large enough that it leaves you some headspace, about 25% of the total volume of vinegar. Take an aquarium air pump, attach tubing and an airstone, and bubble the mixture with the airstone. Cover the container with cheesecloth, netting, or a blue cloth to let air in and keep flies out. Don't ever totally seal a container of in-process vinegar. Oxygen is essential for the fermentation to work. 42 · noma a field guide to fermentation · 43 Taste the vinegar every day. When it is finished it will be vinegary but should still have some of the fresh taste of the juice you started with. If it is still very Advanced Recipe Elderflower and Elderberry Wine Vinegar hot-alcoholic, or smells like nail polish remover, it should be bubbled and oxygenated more. Elderflower Wine Fermentation: Take a tube of White Labs WLP 650 (Brettanomyces bruxellensis) or WLP 568 (Belgian Saison Yeast Blend) yeast out of the fridge to come to room tempera- Vinegar Notes ture before you begin. WLP 650 will make a sweeter vinegar, and WLP 568 will make a drier vinegar. Why add unpasteurized vinegar? Raw (unpasteurized) vinegar has acetic bacteria living in it, and so it acts as a Take 8.5 L of elderflower syrup that is 60 Brix and put it in a 30-L bucket starter or inoculant to get the fermentation going. Vinegar also makes the fer- (which you have already sprayed down the inside of with food grade alcohol) mentation mixture a more hospitable environment for acetic bacteria to chill with 8.5 L of filtered water. Measure and write down the exact Brix level; it out and grow in. should be about 30 (28-32) Brix but make sure you note the exact value and write it down on the bucket. You will need this initial measurement later to Why are we adding alcohol? gauge how far the fermentation has gone. The alcohol is what gets turned into acetic acid by the acetic bacteria. No alcohol, no vinegar. Gently shake the tube of yeast to make sure the yeast sludge that is caked on the side is fully suspended in the liquid. Pour the entire tube of yeast into the Why an aquarium air pump and airstone? bucket, stir it well (with a clean, alcohol-sprayed whisk or spoon) to incorpo- Acetic bacteria need oxygen to live, and by bubbling in lots of oxygen they can rate and aerate it slightly, and put the lid on the bucket with an airlock in the create vinegar in about a week instead of a few months, which is how long it lid. Make sure the airlock is filled with water to the line, and that the airlock often takes without aeration. is capped. As the yeast ferments the sugars in the elderflower syrup, the lid will puff up slightly and the airlock will slowly bubble. As the fermentation progresses, check the Brix value with a refractometer every few days. Enter the starting brix (which you wrote down, right?) and the current brix into the “Monitor Ferment Progress with a Refractometer” calculator available online at the website VinoCalc http://www.musther.net/ vinocalc.html#monitorferment, and read Residual Sugar and Current Alcohol values it calculates. For a sweet vinegar, the alcohol percentage should be between 2% and 4% alcohol. For a dry vinegar, the alcohol percentage should be between 8% and 10% alcohol. 44 · noma a field guide to fermentation · 45 Elderberry and Vinegar Fermentation: • Once the wine has been fermented to the desired level of alcohol, inoculate will the flavor changes that occur during yeast fermentation add or detract from its flavor? with vinegar starter and add elderberries. • For a sweet vinegar (with WLP 650 Yeast): add 3600g of apple vinegar and If you had grapes, you could juice them and add alcohol, but it wouldn't taste 2125g of ripe elderberries (stems removed) to the 30-L bucket with the wine. anything like wine, and a vinegar you'd make out of this would be quite sweet how delicate or unstable is the ingredient you're using? compared to wine vinegar and lack complexity. On the other hand, things like For a dry vinegar (with WLP 568 Yeast): add 4250g of apple vinegar and 9000g celery, asparagus, or pumpkin have some sugar in them, but not enough to of ripe elderberries (stems removed) to the 30-L bucket with the wine. make enough alcohol to get a stable vinegar. Generally 8% alcohol will make a good, stable vinegar; sugar levels of at least 14 Brix are necessary to reach this Keep the lid off of each bucket and cover the open bucket with cheesecloth or level of alcohol. Celery juice, if it sits at room temperature for too long (which other breathable material, and tie off the material so it is secure and flies can't it would have to to ferment into wine), tends to lose some of its fresh flavor and get in. Let the vinegar age and ferment for 3-6 months at 25-30°C. Stir in the get muddied, and doesn't necessarily benefit from having a winey background elderberries that float to the top periodically. flavor. Most of this we figured out by trial and error, but generally the more green/vegetal an ingredient is, the less likely it is to be good as a wine, and the sweeter/more tannic/fruity and concentrated an ingredient is, the more likely More Vinegar Notes it is to be good as a wine. Why do we start with sugar and yeast? What's the deal with the yeast? We need alcohol to make vinegar. Instead of adding alcohol to juice directly Like many of our techniques, we picked these yeasts empirically, i.e. through like for a single-step juice vinegar, we're using yeast to convert sugar into alco- trial and error. Saison yeast is a blend of yeasts that includes Brettanomyces hol, then converting that alcohol into acetic acid. species as well as the more standard Saccharomyces cerevisiae (which is the species typically used for wine, beer, and bread). Brettanomyces is a genus of Why does the elderflower syrup get diluted? wild yeasts that are pretty slow fermenters, and adds some complexity via very With too much sugar, the yeast will either not be able to ferment at all, or we subtle barnyard-y and funky flavors (these flavors are much more pronounced would get a ridiculously alcoholic, ridiculously sweet wine. But the syrup will in wines and beers with a significant Brett-fermented component). This isn't be more stable and takes up less space for storage if it is 60% sugar. to say that regular wine or beer yeast won't work, though. How do you decide to do a yeast fermentation or add alcohol? Where can I find more information on alcoholic fermentations? Key questions to ask yourself are, Generally, we only produce alcohol at noma to eventually ferment it into vinegar. We've experimented with beer-brewing and mead and winemaking; but, • is the ingredient you want to make into vinegar yeast-fermentable—does generally, unless it’s destined for vinegar, we leave the production of alcohols it have sugars in it? to our more talented friends like Mikkeller or Aqua Vitae Sydfyn, not to mention our many wine suppliers. 46 · noma a field guide to fermentation · 47 Why is this one not bubbled with an aquarium pump? How do you decide to do an active Vinegar Variations or a passive aeration? Some ingredients make a better vinegar if they are bubbled or otherwise aerated to very Juice Vinegars rapidly acetify them, other make a better vinegar if they age for a while and acetify slowly. Pumpkin juice, white asparagus juice, celery juice, and fennel top juice all Generally, lower-sugar and lower-acid, vegetal or green-tasting ingredients (such as squash make great vinegars. and pumpkin, celery, fennel tops, asparagus, parsley) are make better fast vinegars: the fast increase in acidity helps protect them from mold and other sources of off-flavors, and Tea Vinegars once they lose their fresh flavors they don’t really develop more complexity. More winelike, Pine tea and other teas work as a substitute for the juice in the above recipe. fruity, or already-fermented ingredients (elderflower wine, elderberries, beer) often develop complexity by a more drawn-out fermentation and so can make a good vinegar either by Wine or Beer Vinegars passive or active aeration. If you have wine already, like cherry wine from Frederiksdal, you can use that with 20% vinegar starter and skip adding any additional alcohol. This tech- Vinegar Trouble-Shooting nique also works with wine you make yourself, beer, sake, etc. The vinegar is boozy and not very acidic: You probably need to wait longer. Acetic fermentation can be somewhat slow especially if you’re not bubbling air through it. If you need it very soon, try bubbling a lot more air through it. Also, sulfur added as a preservative to wines and some beers, fruits, etc. will inhibit the growth of acetic acid bacteria—so try to start with more natural, unsulfured stuff to begin with. The vinegar tastes like nail polish remover: It might not be finished, or it might not be getting enough air—the nail polish remover comes from leftover alcohol reacting with the acetic acid. Try airing it out or bubbling more air through it, or leave it and check again in a few days. 48 · noma a field guide to fermentation · 49 Notes 50 · noma Notes a field guide to fermentation · 51 Notes Chapter Five Koji Steamed then mold-inoculated grains Process: Aspergillus oryzae mold grows on grains, breaking down their starches and proteins for food, releasing useful enzymes in the process Necessary components: Grains, steam oven, Aspergillus oryzae spores 52 · noma a field guide to fermentation · 53 Basic Recipe: Barley Koji Steaming Soak pearled organic barley in cold water in the refrigerator overnight. The next morning, put the soaked barley in perforated gastro trays, rinse it with cold water in the sink, and steam it in the combi oven at 92°C, 90% humidity, and fan speed 80%. Take the barley out of the oven, and break it up gently into individual grains with your hands while it’s hot, which helps stop it from getting too wet and clumpy (try wearing two pairs of gloves to do this). Discard any barley that’s become very soft and overcooked from pooling water or condensed steam. All the grains should be separate, cooked through, and firm, but not soft, mushy, or slimy. Inoculation Divide the barley up into several perforated gastros in a depth of about 4 cm. Wearing gloves, put spores of Aspergillus oryzae into a small tea strainer and tap the strainer over the cooled steamed barley. Do one light pass with the spores in the tea strainer, mix/fold the barley with your hands to incorporate the spores, then do two more light passes each followed by folding the barley to mix the spores in. If you’re using spores you grew yourself, put the dried sporulated koji in a powdered sugar shaker and shake it on in three passes. Mold Growth Cover each tray with a very clean cloth that you’ve soaked in water and wrung out well. Put the trays of inoculated barley in a clean, warm room (not an oven) with the temperature set to 33°C and humidity of at least 80%. Ideally, temperature should be controlled through a PID box; insert the temperature probe into the inoculated barley for the duration of the mold growth phase. EXTREMELY IMPORTANT: During the mold growth process it is very easy for the koji to overheat and kill itself. WATCH THE TEMPERATURE of the koji and make sure it doesn't go above 39°C. 54 · noma a field guide to fermentation · 55 After about 24 hours, the barley should be showing some visible mold growth. Koji Notes Gently crumble it with your hands into individual grains, fold the outer grains into the center of the tray so it is well-mixed, and make two shallow, even- Why pearled barley? ly-spaced furrows all the way down the middle of the barley in the long direc- Removing the barley husk makes it easier for the mold to reach the starch in tion to make three long rows of heaped barley in the tray. the grain, and it will ferment the grains more completely. It's possible to make un-pearled or unpolished grains into koji, but they tend to sporulate faster and Let the mold grow on the barley for about 12 hours more, until the white mold don't get as sweet. of the Aspergillus binds the barley together into a solid cake and looks slightly fuzzy. At this point, the barley will taste sweet and slightly fruity, with a savory Why soak and steam the barley? and mushroom-y aftertaste. Try to stop before it looks extremely fuzzy, with The ideal medium for growing Aspergillus is hydrated, but separate and rel- tiny balls of mold among the mold hairs— at this point, it is starting to produce atively firm grains. Boiling the grains tends to over-hydrate them and make spores (sporulate) and won't be as tasty or effective. them too wet and mushy. This makes it too easy for the mold to grow quickly just on the surface instead of expending energy to produce enzymes to pen- Use the koji right away or refrigerate for up to three days. Cool the koji in its etrate to the middle of the grain. We want the enzymes so we want to cre- trays in the walk-in before putting it in a container. To store for longer, put it in ate conditions that make it a little trickier for the mold cells to grow too fast. vacuum bags, freeze, and then seal to store in the freezer. Over-hydrated grains also tend to stick together and create poor conditions for airflow, choking and killing the growing mold below the immediate surface layer of the grains Why crumble the barley up by hand? This ensures that the barley cools off evenly and gives up its extra moisture, that each grain gets evenly coated with spores, and that air can get to each grain. Why inoculate with mold spores? Unlike beer, sourdough, or other yeast and lactic fermentations, it's not possible to simply “back-slop” or inoculate a new batch of koji by adding a small amount of finished koji or miso to new barley grains. Instead, the mold has to be grown past the stage in its life-cycle when it's useful for miso, koji water, etc. and until it enters its reproductive phase and starts producing spores. These spores are like seeds for new koji, and by collecting them and sprinkling them on freshly steamed grains, you can grow a new mold colony (your koji!) 56 · noma a field guide to fermentation · 57 Why the high humidity? molecules with complex flavors; sugars are also tasty, but more importantly The mold needs the environment to be relatively moist to grow properly, but can be fermented into new flavors by lactic bacteria, acetic bacteria, and yeasts. not actually wet. Whether the koji you produce is richer in amylases or proteases—whether it is more effective at breaking down proteins or starches—depends on tempera- Why 33°C? ture. Proteases are produced more effectively close to 30°C, and much less The barley needs to be pretty warm for the mold to grow on it properly, and in effectively at higher temperatures (38°C or higher), whereas amylases are pro- the 30-35°C range it produces a lot of useful enzymes that break down starch- duced well at both temperatures. To dial in a particular balance, it is essential es into sugars (which are sweet and can be fermented) and proteins into free to maintain precise temperature control of the koji while it is growing. amino acids (which have an umami flavor and can break down into aromatic compounds). Why can't I just put it in the Rational or Combi Oven? While a Rational can be set to 30°C, it has temperature spikes and drops when Why furrow the inoculated barley? holding at 30°C. It will drop down to 20°C at some points, which is not great Starting about 24 hours after inoculation, the koji can heat itself up to 40-45°C for keeping the barley growing; it will also spike to 40°C or more for about or higher, which is hot enough to kill the mold cells; furrowing helps dissipate 10 minutes at a time, which will kill the mold and your koji. More gentle and some of this heat. The mixing also incorporates the parts where the mold is precise temperature control is needed, which can be accomplished in a heated growing faster, leading to a more evenly fermented final product. room or in a chest-freezer sized box, especially with the heating controlled by a PID box (the kind of temperature control that sous vide machines have). Why do I have to be so careful with the temperature? Koji and Aspergillus oryzae are very sensitive to temperature—as mentioned Why all this fuss? Why do I want to make koji? in the recipe, the mold can give off enough heat during its growth phase that Acknowledgement: out of any of the techniques in this book, koji-making is it can cook itself to death. But besides ensuring that your mold actually sur- probably the most finicky and the biggest pain in the ass to figure out. It needs vives, controlling temperature will also determine how effective the koji is at to be exposed to air, but not so much that it dries out; it needs to be kept within second-stage fermentations you want to use it for. Pretty much all living cells a relatively narrow temperature range, which means warming it at some points produce enzymes, which are protein molecules that build, break down, or alter of the process and cooling it at others; it needs to be kept very humid but not other molecules; they are the machinery that, on a molecular level, perform the so humid that water starts to condense on the surface of the grains; it needs processes that keep a cell alive. Enzymes are usually named as “the thing they to be tended to at several time-points in its fermentation period; and the nec- break down”+ “ase.” If you see a world ending in “-ase,” there is a good chance essary amount of, and parameters for, soaking and steaming vary widely for it is the name of an enzyme, and the word(s) coming before “-ase” describe more uncommon but interesting ingredients like buckwheat or bread. How- its function or the molecule that it breaks down. The two classes of enzymes ever, with a few technical interventions, it can be made pretty reproducibly. in koji that are most useful to us are proteases and amylases. Proteases break Currently we use a 3-4 sq. meter room, where a humidity sensor controls a down proteins into their component amino acids, and amylases break down fogger, and the temperature in the room is controlled by a PID box connect- starches (made of amylose and amylopectin) into their component sugars. ed to a thermometer and an infrared heating panel. We’ve also used a broom These processes are useful because free amino acids are delicious and taste like closet with a space heater and home humidifier, and a chest freezer lined with umami, and they also break down and react with other molecules to make new an under-floor heating mat with heating and cooling cycles controlled by PID 58 · noma a field guide to fermentation · 59 and open containers of water for humidity. A decent amount of air circulation noon, this often happens in the morning or afternoon the next day - and this is necessary for avoiding over-heating, so producing koji in small styrofoam killed the Aspergillus cells, and a heat-tolerant bacteria called Bacillus subtilis coolers or thermal boxes is more likely to result in dead koji. started growing instead. This is useless for fermenting anything else and you should throw it away. Once you put in the work and attention to make it, koji has possibly-endless, near-magical abilities to create flavors and transform other ingredients, en- The Koji has a bunch of black spots or black fuzzy mold on it: abled by the enzymes produced by Aspergillus oryzae as it grows. These break This seems to happen when the barley is too damp. Make sure that the perfo- down large molecules into smaller components—starches into sugars, and pro- rated tray you’re using has lots of holes that extend as far to the sides as possi- teins into amino acids. These molecules have flavors of their own, fuel further ble to ensure maximum airflow and avoid condensation. Also make sure that fermentation processes, and react and break down to make more flavors. Many you discard any barley that has become waterlogged and soft from being over- of the most interesting uses for koji kill off the remaining mold cells (with salt steamed before you inoculate. You’ll often be able to catch a batch that’s going and/or lack of oxygen) and hijack their enzymes to transform a second ingre- to go wrong when you do the first turning; if you see any areas that are getting dient like peas, beef, or rye bread. black specks on the barley, or that feel particularly sticky, discard these and the rest of the tray might still be usable. This might be a mutation in the Aspergillus oryzae—all koji molds started out as black and were bred and mutated Koji Trouble-Shooting to become white—or it might be another species; in any case, don’t use it for anything. The Koji is a solid, white slab or cake and smells pleasantly fruity/bread-y/ floral/ mushroomy and tastes sweet: The temperature of the Koji keeps going to 40°C or higher: Congratulations, you did it right! The koji produces heat as it grows. You need to keep an eye on the temperature and help dissipate that heat - break up the koji with your hands, fold it over it- The Koji is slimy and smells like feet, rotting onions or something equally self, and make furrows in the barley. You can also try cooling the room actively unpleasant: at this point, and keeping some space around each tray for air to circulate and The Aspergillus oryzae spores weren’t able to grow, and a spoilage bacteria/ stop heat buildup. mold took over. This usually happens when the grains are too wet, and air can’t get to the stuff on the bottom and it all kind of putrifies. If you boil the barley or I made Lacto Koji Water and it smells like rotten eggs: whatever other grains you’re using (quinoa, millet, buckwheat, anything with a First, throw it away and don’t use it. Second, make sure you use twice as much husk that is hard to steam) this often happens. It’s also possible that you didn’t water as koji and 2% salt, and check it every day. Also make sure that all your let the grains cool off enough before you inoculated them, and the Aspergillus equipment/hands are very clean. died at that point. Definitely throw it out and start over. The Koji is sticky and there’s not really any mold growth and it smells like rotten banana/fruit: The koji probably got overheated—if you start the growth in the early after- 60 · noma a field guide to fermentation · 61 Uses for Koji Lacto Koji Water Take 500 g of finished koji, 1000g of filtered water, and 30g of fine salt. Blitz in a Thermomix to combine, and seal in a vacuum bag as close to 99% vacuum as possible without bubbling over. Let ferment for 3 days at 25°C until the bag is swelled. The Lacto Koji Water should taste clean, fruity, lightly acidic, and creamy, with no eggy aroma. Roasted Koji Sauce (Mole) 750g Roasted Koji 1000g Cream 600g Milk Roasted Koji Break the Koji down into small as possible pieces and roast it 160°C. Turn or shake the koji every 10 min to get an even roast on it. After approximately 1 hour the Koji should smell a bit like roasted coffee and also should have the colour of it. After it’s cooled down, combine 750g roasted Koji with 1 liter of cream in a vacuum bag it and allow to infuse overnight in the fridge. Once rehydrated, add 600g of milk and blitz in a Thermomix on 70°C to a paste consistency. Pass it through a sauce net while still warm. Place into vacuum bags when cool and store frozen. Koji Salt 300g fresh koji 300g salt 300g water Blitz the ingredients in a blender and reserve in the fridge. This is an excellent cure for meats, particularly game birds. Aspergillus oryzae conidiophore (spore cell) 62 · noma a field guide to fermentation · 63 Misos, Shoyus and Garums Notes Koji can also be used as a component in more complex fermentations involving different proteins. Misos and Shoyus (chapter 6) at noma involve koji and legumes, nuts, grains, leftover vegetables, seeds, or coffee ; Garums (chapter 7) involve animal proteins. 64 · noma a field guide to fermentation · 65 Notes Chapter Six Miso and Shoyu Nuts, legumes, grains, or other plant material fermented and aged with koji and salt Process: Koji enzymes break down starches in legumes into sugars, which are fermented by lactic bacteria, yeasts, and acetic bacteria; proteins are broken into umami flavors Necessary components: Koji; yellow peas, nuts, or bread; salt; bucket; rock 66 · noma a field guide to fermentation · 67 Basic Recipe: Pea-so (Yellow Pea Miso) 3000g Cooked Yellow Peas 1900g Inoculated Barley Koji 200g Fine Salt Soak approximately 2000g dried yellow peas in cold water overnight. Strain and wash. Weigh the peas—they will increase by roughly 50% in weight. Seal 3000g of the soaked peas in a vacuum bag with 1000g of water and cook in a steam oven at 100°C for 2 hours. Cool down to room temperature. Strain the peas and reserve the cooking water. Mix 3000g of cooked yellow peas and 1900g of finished Barley Koji (inoculated, molded pearl barley—see section 4 for more information). IMPORTANT: The moisture content of the mixture is extremely important, and will determine the success and flavor of the final product. Too much water will encourage an excessive activity in the onset of the fermentation, leading to an aggressive acidity or sharpness. Too little water and very little will happen. Take a small amount in your hand and clench your fist—the substrate should form a dense, bound paste. If a little sort of oozes between your fingers it is too wet, and if it remains crumbly, it is too dry. When the yellow pea-koji mixture is the correct consistency, weigh it and add 4% of that weight in fine, non-iodized salt. For this recipe that will be approximately 200g. Mix it well to make sure it is homogenous, and put the mixture into a 12L nonreactive container, taking care that there are no air pockets. Cover the surface with cling film, ensuring the surface is not exposed to air. Place a plate on top of the clingfilm and load with 5 kg of weight (a clean paving stone in a vacuum bag, or a 5L container of water are ideal). Cover the container with a cloth to prevent contamination from flies, etc., and secure the cloth with a rubber band or string. Age the pea-so for at least 3 months, and up to 6 months, at an ambient temperature of 25-33°C. The aged pea-so should be lightly acidic but not overly sour. 68 · noma a field guide to fermentation · 69 The pea-so can be frozen at this point, or cooked off and passed before using in lactic, yeast, and acetic fermentations as it ages, and being under a cloth, plate, dishes or further storage. and plastic wrap instead of a hard seal helps stop it from getting too yeasty or boozy. If not being frozen, the peaso should be cooked off and passed before using in dishes or further storage. Why cook off or freeze the pea-so? Cooking will kill off all the microbes in the pea-so, as well as denaturing (basically, breaking) the enzymes present. Skipping this step means the fermenta- Pea-so Notes tion will keep going as the pea-so is stored, altering its flavor. Freezing will also radically slow the fermentation and aging process. Cooking off the pea-so also Why peas and why koji? remediates any off-flavors, like the aforementioned nail polish remover smell, What you're doing here is using the enzymes created by Aspergillus oryzae that sometimes develop during the fermentation, especially if you made the (when it fermented the barley into koji) to break down the starches and pro- pea-so on the wetter side. teins in another legume or grain, in this case yellow peas, to flavorful and fermentable components. Koji is needed to supply these enzymes, and yellow Why use yellow peas in particular? peas are the protein source. When we began looking into making a miso-style fermentation, but with Nordic ingredients, it was necessary to find an analogue to soybeans, which are Why 4% salt? in no way Nordic. The point of making a miso is to develop umami flavors by To age at room temperature safely and develop good flavors, salt is needed to breaking down proteins in an unfermented ingredient with the enzymes de- impede spoilage bacteria and encourage lactic acid bacteria to grow. Generally, veloped by the molded barley koji, so we needed something that was high in the longer the miso is going to age, the more salt you need to add (or, the more protein. Fortunately the Danish Technical University (DTU) publishes infor- salt you add, the longer it needs to ferment). mation about the nutritional breakdown of various Danish food plants; on their website we found that yellow peas have a particularly high amount of protein, Why weight the pea-so? so we made a “pea-so” out of yellow peas that turned out to be very tasty. Weighting the pea-so helps prevent air pockets, and pushes excess liquid to the surface. It also keeps most of the pea-so surface out of contact with air, while letting it breathe and off-gas as needed. The weight placed on the pea-so should be approximately equal to the weight of the miso. Why not just vacuum-seal the pea-so? Completely sealing the miso will keep it out of contact with oxygen. But we want a little bit of contact with the air to let off any gaseous products of the fermentation and break down/oxidize some of the mid-fermentation aromas which can smell somewhat like nail polish remover. The pea-so is undergoing 70 · noma a field guide to fermentation · 71 Miso Style Trouble-Shooting Miso Variations The miso is bubbling: Rye-so (Rye Bread Miso) This is normal, especially at the beginning of the fermentation. Take 3000g of Danish Rye Bread, and blitz to a crumble. Add 2000g of blitzed koji, and mix in water until a proper firm-paste consistency is achieved. (This The miso is quite boozy and sweet and has a Hefeweizen-banana smell: may be almost 2L) Calculate 4% of total weight (allowing for the salt in the You are at the yeast-growing phase of the miso fermentation; if you want it to Rye Bread, which in our case is 1.7%) and add this amount of fine non-iodized be quite sour and have more umami flavor, you need to let it continue going for salt, and incorporate thoroughly in a nonreactive container. Cover the surface a while longer, so that the acetic and lactic fermentations can happen, and the with clingfilm, a plate, and a weight as above for pea-so, and age for at least 3-6 proteases in the koji (which act more slowly) can do their thing. weeks. There is some white mold on the surface or around the edges of the miso: Nut Miso (Hazel-so, Wal-so, Pumpkin-so) This is fairly normal. To stop lots and lots of mold from forming you can (light- Take 3000g dry nut pulp (leftover from making nut oil) and 2000g of blitzed ly!) sprinkle non-iodized salt over the surface of the miso before you put plastic koji, and mix in water until a proper firm-paste consistency is achieved. (This wrap and a plate on top of it. may be almost 2L) Calculate 4% of total weight and add this amount of fine non-iodized salt, and incorporate thoroughly in a nonreactive container. Cover The miso smells like nail polish-remover: the surface with clingfilm, a plate, and a weight as above for pea-so, and age Fermenting miso is a balance between too much air circulation, which allows for at least 3-6 weeks (start tasting after 10 days). The nut miso are especially not-so-good molds to grow, and not enough. If you don’t have enough air cir- sensitive to excess water content, and will be very sour if too much is added, culation and off-gassing, odd flavors can build up. So make sure you haven’t so it’s better to err on the side of dry. If after 10 days the mixture is still too sealed off your miso completely with plastic, and don’t try to ferment it in a dry, compact, and sandy textured, mix in a small amount of water with 4% salt vacuum bag. dissolved in it until it has more of a paste-like consistency. The miso smells like blue cheese, or like rancid fats: Flavored Pea-so (here we often use byproducts from other processes) These are the flavors that happen from fats, especially milk fats, breaking down 3000g Cooked Yellow Peas enzymatically yielding blue cheese flavors, or from unsaturated nut fats oxidiz- 1900g Inoculated Barley Koji ing and yielding rancid, paintlike flavors. If you can press or spin out the fats 500g Elderflower, Wild Rose, Thyme, etc. (We use the leftover pulp from from your substrate, you’ll avoid these flavors. oil production for this) If using fresh pine, limit to 5% (250g here) 200g Fine Salt The miso has just become very acidic very quickly: This is often an issue of excess circulation, where there has been too much air Combine and ferment as for Pea-so recipe. and water available for the yeast and acidic bacteria, and they have propagated at a higher than desired rate. Too much liquid in the mix and/or not enough weight pressing evenly on the miso can also cause this. 72 · noma a field guide to fermentation · 73 Bread-so Dryad's Saddle Shoyu 2000g Bread Koji 1000g Dryad’s Saddle Mushroom, blended to a paste 3000g Toasted Bread 200g Koji Filtered Water for consistency 300g Filtered Water 4% Salt of above weight 60g Salt First, make bread koji: take leftover sourdough bread, remove crust, and cut Incorporate all the ingredients with a large stick blender. Place in a suitable into a rough macedoine. Lightly dust with Aspergillus oryzae spores and place container with the surface covered with clingfilm. Age at 33°C for 6 weeks. in a suitable environment for mold growth (see Koji section for more detailed Press through a superbag. instructions) Take another batch of leftover bread, toast to a golden brown and blitz to a crumble. Mix with the finished Bread Koji, add water just until a firm paste is achieved. Calculate 4% salt, and incorporate with a large stick blender. Press firmly into a suitable container, cover surface with clingfilm, and load with 5kg of weight. Vegetable Shoyu 1000g Vegetable (pumpkin scrap leftover from juicing for pumpkin shoyu, or cabbage juice from leftover cooked cabbages for cabbage shoyu) 100g Koji 44g Salt Blend well, put in a bucket, cover with clingfilm, and age at 60C for 3 weeks. Strain and use the liquid. Coffee Shoyu 4000g Koji 1000g Spent Coffee Grounds (after brewing coffee) 5000g Filtered Water 200g Salt Blend well and age at 60°C for 4-6 weeks. Strain and use the liquid. 74 · noma a field guide to fermentation · 75 Notes 76 · noma Notes a field guide to fermentation · 77 Notes Chapter Seven Garum Animal proteins, aged with koji and salt Process: Controlled enzymatic breakdown of animal proteins by koji in a highly salty environment Necessary components: Koji, animal protein, salt 78 · noma a field guide to fermentation · 79 Basic Recipe: Grasshopper Garum (Fermented Grasshopper and Koji Sauce) 1000g Protein 225g Barley Koji 300g Filtered Water 240g Fine Salt Blend 600g of wax moth larvae (they come frozen, in boxes) and 400g of grasshoppers well in a thermomix or blender to make a paste. Incorporate the grasshopper and larvae paste with 240g of fine salt, 300g of filtered water, and 225g of finished barley koji in a non-reactive container. Press plastic wrap onto the surface of the garum to keep it out of direct contact with the air. Incubate the garum at 60°C for 10 weeks. A PID box with heating and a temperature sensor is useful for this (see Appendix B for more details). The mixture will separate into liquid at the bottom and solids at the top. The liquid (garum) will be a golden brown, and the solids a lighter orangey-brown. The garum should smell meaty, toasty, and slightly cheesy (like parmesan, not like blue cheese, camembert, or tallegio). Decant the liquid at the bottom with a pipette or siphon, then blitz and pass the solids through a fine sauce net before use. 80 · noma a field guide to fermentation · 81 Garum Notes add koji instead of fish guts to supply the protein-digesting enzymes, but the process is similar. The garums we produce at noma are also similar in process What is going on in this recipe? to the chiang and miso produced in ancient China and Japan from rice qu/koji, You're breaking down the proteins in the insects into delicious free amino ac- meats, and salt before soybeans were widely used. ids (what are very umami) and other tasty flavors, and controlling this breakdown/slow rot with high levels of salt. Garum Trouble-Shooting Why grasshoppers and wax moth larvae? This just seems very sketchy. Insects contain high levels of protein, which on its own doesn't have a lot of Actually the garums are the safest, simplest and easiest of the ferments to con- flavor. But, when these proteins are broken down into amino acids by the pro- trol. The high heat, and relatively high salt content protect them from the great teolytic enzymes (proteases) in the koji, rich umami taste develops as well as majority of unwanted microbes. other toasty and cheesy flavors. The fish/shellfish garum smells….really dodgy. Why salt? Sorry. It always does in the beginning. This is normal. Man the fuck up. But if For grasshopper garum you add about 11% salt, which is 3 times as much as for after a while it smells like the ocean took a dump on a dead whale, you should misos. This percentage of salt will slow most microbial activity, including lac- start with fresher fish/squid/etc next time. tic acid bacteria, to the point where garum won't develop much acidity and is instead more of a controlled rot/enzymatic breakdown of the meat and larvae So….I left it alone like you said, and it’s gone from really dodgy-fishmarket proteins. to pure death-smell. It cannot be reiterated enough that the product must be extremely fresh. This Why Koji? process is not for the things you forgot about in the fridge and that already Koji has a lot of enzymes in it that are good at breaking down proteins, which smell like a street urchin with the black plague. If it’s not fresh enough to eat, helps speed up the process of producing garum; this speeded-up breakdown it’s not fresh enough to preserve. also allows for the use of less salt for a more versatile sauce. Why hold at 60°C? Heating up the garum helps it break down the meat protein faster, and at 60°C the umami flavor and caramelized flavors are most emphasized; at higher temperatures it will ferment faster but can taste over-browned. Why do you call it garum? Garum was one of the most popular sauces in the ancient Roman era, and was made much like Thai or Vietnamese fish sauces are today, with the flesh and guts of small fish and lots of salt left to ferment and break down over time. We 82 · noma a field guide to fermentation · 83 Garum Variations Notes Beef Garum 600g Beef, ground 400g wax moth larvae 800g filtered water 240g salt Blend 400g wax moth larvae in a blender or Thermomix until smooth. Mix this puree by hand with 600g of raw beef trim or ground beef, 225g barley koji, 800g filtered water, and 240g of salt until well-combined. Cover, ferment, and process as for grasshopper garum, above. Squid Garum 1000g Squid Trim 225g barley koji 800g water 240g fine salt Grind the koji, water, salt, and squid trim (guts, ink, tentacles, everything except the clear pen or gladius) into a rough puree using a Thermomix, robot coupe, or meat grinder. Cover and ferment as for grasshopper garum, above. This recipe works well with any kind of very fresh shellfish trim. Lobster bodies, mahogany or razor clam scraps, the goop leftover from cleaning sea urchins—these have all made fantastic garums. 84 · noma a field guide to fermentation · 85 Notes Epilogue Fermentation… 86 · noma a field guide to fermentation · 87 Some time ago we were showing a pair of chefs from a two star restaurant to make a sufficiently umami-rich and flavorsome hazelnut miso-style ferment around our fermentation kitchen, going through the different processes, and because of the high amount of oil in the nuts which would impart a distinct the multiple applications they are associated with. After about thirty minutes rancidity after a week or so. Some time later, we began to press our own oils, or so of careful, attentive nods of comprehension the senior of the two inter- mostly hazelnut, and after binning the dry and somewhat tasteless left-overs rupted me, his brow furrowed. “So—is that fermentation?” pointing at the vin- from the nut press we had one of those head-slapping moments— this ‘garbage’ egar room, “Or is that?” gesturing to the steam filled chamber of ‘koji.’ Despite (which of course was only that because of the way we thought of it) was exactly my efforts to the contrary, everything had remained a mystery, a hall of smoke what we had needed for the miso-style ferment. All of the hazelnut besides the and mirrors. Some of the cooks at our restaurant have a similarly vague grasp of oil. So now we occasionally find ourselves pressing oil just to have the ‘garbage’ what methods lead to which results, only aware that products go over to the lab left-overs for making the Hazel-so. to be put into buckets or bags, and after some period of time come back tasting remarkably different. The Squid Garum was similar in a way; laden with the knowledge of how garums were historically made from the innards of Mediterranean fish, it still It is important to remember that fermentation is cooking. There are different somehow took us a while to make the cognitive leap to the guts of the squid tools, different timeframes, perhaps a new skill set to learn, but nothing more we had been throwing in the bin. Now we make a range of delicious fermented dramatic than learning to make sauces, work a grill, or proper butchery. Com- sauces from every scrap of shellfish and meat that gets processed by the restau- mon sense and curiosity must balance each other, as always. “How dangerous is rant. all this?” is a common question we field from guests. The answer is that it’s no more dangerous than cooking anything else. If a person cooks fish they should In the end, this ‘head-slapping,’ however frustrating, should be seen with opti- know how to tell if it is fresh enough to eat. The same is obvious for vegetables. mism—it indicates that, despite working on these things for several years, we Bread, wine, and beer are often made by home cooks with impunity, because are only scratching at the surface, with a wealth of discoveries waiting to be these fermentations are part of our culture. The methods outlined here only stumbled upon. In finding these there will of course be questions, unknowns, require the same care and attention that would be a part of any cookery. wandering off the common path and forays into dead ends and unexplored territory. Many things you may try might not be easily Googleable, might require This Field Guide is only intended to be a primer to the processes of fermenta- trolling through patents and academic papers to get an opaque suggestion tion, a framework to build upon. The hope is that by sharing a few successes about what you should be doing, but that’s the whole point. We attempt to re- and a lot of failures, we can further a collaboration in the greater community, tain our skillset while discarding our biases and routines. It is always the lines where we might all benefit from each other's work. The ingredients we have we cannot see, our preconceptions, that are the hardest to cross. used here are merely the ones we find around us—if pistachios grow in your part of the world, make a miso out of those, or if you come across sumac in your There are steps you can take to ensure that you’re not setting yourself up for landscape, that would be ideal for a kombucha. failure. Cleanliness, sanitation, and exhaustive tasting as each process evolves are paramount. Flavor dominates, and flavor is the strongest tool you have to tell The greatest successes often seem obvious in hindsight, and may come upon you if everything is working as it should. Of course, each of these techniques is one with a resounding slap of the forehead, or in complete serendipity. The only as good as the ingredients you put into them; lacto-fermenting shit quality Hazel-So of which we are currently fond was borne on both: we had struggled cherries only leads to shitty lacto-fermented cherries. Lacto-fermenting beau- 88 · noma a field guide to fermentation · 89 tiful wild cherries in their prime will allow the sublime to emerge. The same Notes is true for Squid Garum—it is a technique that transforms a waste product into something really special, but it can’t save bad fish; good Squid Garum comes from product that is good, fresh, and high quality to begin with. Perhaps the most critical thing to remember is that nature will not be denied; life finds a way. Something is going to grow. The best bet is to provide an advantage at the outset for the species that you would like to win. We established a Fermentation Kitchen at our restaurant as we began to incorporate these techniques into our entire menu, from the first bite to the desserts and petits fours, and as we expanded the techniques we have used for many years. Now practically every ingredient, whether oil, vinegar, spice, or umami rich paste, is painstakingly produced at the restaurant, which gives us certain flavors that cannot be reproduced elsewhere—beautiful local produce transformed by the microbes around them, a logical extension of time and place as seen through the paradigm of deliciousness. If one were to bring Copenhagen ryebread to New York, and make Rye-so there, it would taste different, due to the local microbes. There is a palpable joy in tasting something new, and traveling to savour something which tastes of its place, its landscape. But there is an even greater joy in creating or discovering a new flavour, and we hope that you will not only try to replicate the recipes here, but embark on your own explorations, so that we in turn may be inspired. 90 · noma a field guide to fermentation · 91 Notes Appendix A Control and Safety with Fermentations 92 · noma a field guide to fermentation · 93 “Controlling” a fermentation means making sure only the microbes you want Salt to grow are growing, and that they're producing optimal flavors. If you’re doing lacto-fermentation (e.g. lacto plums) or fermenting anything with koji (koji water, miso, shoyu, garum) you’re going to be using salt. The basic methods for controllingways you control a fermentation are through salt, pH/acidity, water activity, oxygen levels, temperature, food/energy Lactic acid bacteria (LAB) are able to tolerate salt concentrations that most source/substrate, and inoculation. Necessary controls for each type of fermen- yeasts, molds, and other bacteria can’t grow in, so salting is an effective way tation are included in specific recipes; this is a more general discussion about to control what types of microorganisms can grow. We use salt concentration what these controls are and how they work. ranges between 2% and 4% to suppress spoilage bacteria and molds and let lactic acid bacteria proliferate and produce an acidic environment. We use higher For any of these fermentations, a clean workspace, clean hands, and washing salt levels, around 11%, to suppress LAB along with other microbes and enzy- your ingredients are the most basic safety parameters you can follow, as is be- matically ferment and break down animal proteins in a controlled manner for ing sure to throw away anything you feel unsure about or that smells “off.” garums. For anything that’s not acidic (below pH 4.6), and not going to become acidifed by lactic or acetic bacteria (for example, garums) salt levels well above A note on botulism 7% should always be used to ensure safety from dangerous microbes like Clos- Botulism is a very rare but potentially fatal paralytic illness caused by botuli- tridium botulinum. numm toxin, a neurotoxin produced by the bacterium Clostridium botulinum. The reason you should care about it is that, unlike most other forms of spoilage, Acidity and pH it is not detectable by smell. C. botulinum requires a protein source, a relatively Acidity inhibits the growth of molds and other spoilage microorganisms. Lac- warm temperature, and a completely anaerobic, low-salt, low-acid, low-sugar tic and acetic bacteria both produce acidity as they ferment, which helps pre- environment to grow. For this reason it tends to grow in improperly canned serve the products we make with them—lactic fermentations, vinegars, shoyu, meat and improperly preserved fish. Acidity levels below pH 4.6, or salt levels miso—and also makes them taste sour. Acidity is manipulated in vinegars and above 7%, are each able to protect from botulism. Salty, acidic foods that have kombuchas, and created in the course of these and lactic fermentations, as well lactic bacteria growing in them are even safer. So, for protein-rich fermenta- as in shoyus and misos tions, rapid acidification and sufficient levels of salt, as well as avoiding a completely oxygen-free environment, are all essential for safety. This doesn’t mean Acids taste sour—lactic acid, acetic acid, citric acid, ascorbic acid (vitamin C), you should be afraid of them, but that you should be especially cautious about and malic acid are all organic acids which may be familiar to you. Most fruits doing these fermentations properly. produce varied ratios of citric, malic, and ascorbic acid. Lactic acid is produced by lactic acid bacteria as a by-product of their use of sugar as fuel; acetic acid is a similar by-product of the metabolism of acetic bacteria fueled by ethyl alcohol. Molecules which create acidity and have a sour taste do so because when dissolved in water, a hydrogen ion (or several hydrogens in some cases) detaches itself from the main body of the molecule. The more hydrogen ions that are dissolved in a solution, the more acidic it is and the more sour it tastes. 94 · noma a field guide to fermentation · 95 pH is a measure of acidity; somewhat confusingly, pH is a reverse scale, which definition of fermentation). Acetic bacteria and Aspergillus oryzae both re- means that the lower the pH, the higher the level of acid (measured as hydro- quire oxygen to make vinegar and koji, respectively. gen ions) present. A pH of 7 is completely neutral; below 7 is acidic and above 7 is alkaline/basic. Temperature Controlling temperature lets you control the speed at which you’re ferment- Higher levels of acidity (or lower pH levels) create less hospitable environ- ing and the growth of different types of microbes, both of which are import- ments for the microbes that would ruin a fermentation or render it unsafe— ant for safety and flavor. You can manipulate temperature to make the things including many molds, Clostridium botulinum (the bacteria responsible for you want to grow, grow very fast; or amp up the activity of different enzymes botulism), and other spoilage and pathogenic organisms. which can speed up flavor development (we heat misos to 33-35°C and Garums to 50-60°C to boost amylase and protease activity). You can also slow down Generally, the rule of thumb where foods are safe is pH 4.6—at or below this things you don’t want to grow and prevent off-flavors—lacto-fermentations of level, there is enough acidity to halt the growth of dangerous microorganisms fruits and vegetables are kept at a lower temperature than misos to slow yeast like Clostridium botulinum, which can grow in low-acid, low-salt, low-sugar, growth, for example. See the section on temperature control later in the book low-oxygen environments. for examples of target ranges. (It’s also possible to use high alkalinity to preserve foods; Chinese century Substrate eggs, which are cured in lye, are one example of this. We don’t really have a You can think of using substrate (the ingredient or material you’re fermenting) dedicated taste receptor for alkalinity the way we do for acidity so alkaline to control the fermentation process in two ways: foods tend to taste slightly bitter or soapy). 1. Deciding on a product you want to end up with, like lacto-fermented In aerobic conditions, a low pH can help stop the growth of undesirable sur- berries, kombucha, or garum, and then picking a substrate that has the face molds that would cause spoilage. right composition to make that product, like berries, something that can be made into tea, or something to grow the koji and a tasty fresh animal Oxygen protein. Certain processes like mold growth and acetic fermentation, can only happen in the presence of oxygen, so when we would prefer these not to occur, we 2. You have a lot of ingredient X (for example, clam guts) and want to fer- remove oxygen from the fermentation environment by sealing in a vacuum bag ment it. Based on your understanding of the composition of ingredient X or with an airlock. When we do want them to happen, like to make koji or vin- and how different fermentation processes work, you can figure out what egar, we make sure that a lot of oxygen is available. you need to add or do to make these act effectively on it, or what is the ideal fermentation to use with it (in the case of clam guts, probably a garum.) Microbes and the fermentation processes they perform can generally be divided into those requiring oxygen (aerobic) and those which require or prefer the absence of oxygen (anaerobic). Yeasts and lactic acid bacteria both perform fermentations without oxygen (recall that these follow the strict biochemical 96 · noma a field guide to fermentation · 97 Understanding the relationships between substrate composition and microbe Inoculation happiness is probably the most important tool for experimenting with fermen- Some fermentations will proceed quite happily from microbes that are hang- tation successfully. This lets you know what you CAN do based on what you ing around in the environment—this is how we do lactic fermentations, and have, and what’s likely to be a nonstarter. This isn’t to say that you shouldn’t it’s the basis for natural winemaking. In other situations, it is useful in the be- experiment and take a chance on something which might not work—but that ginning to add a dose of the microbes you want to be the dominant actors in knowing the basics will make your experimentation smarter, faster, and more your fermentation, so you can make sure that they outcompete less desirable delicious. or dangerous strains. Some of these substrate basics: This is especially important in dicier conditions where the microbes that grow spontaneously may have nasty side effects; if you’re making conditions to in- • if there are no sugars, it won’t lacto-ferment. tentionally encourage mold growth, you want to make sure the right kind of • if you don’t have any alcohol, you can’t make vinegar. mold is growing. • Aspergillus oryzae can thrive on starches, but not so well on cellulose. Cel- • lulose is made out of linked glucose molecules but has different linkages Some fermentations won’t proceed at all without inoculation. The community that the amylase enzymes in starches aren’t able to chomp on. So koji will of yeasts and bacteria that transforms sweetened tea into kombucha doesn’t re- grow rather poorly on unstarchy vegetable matter. ally exist or hang around in the wild—it needs to be inoculated by transferring misos and garums develop flavor by breaking down starches and proteins a community from old kombucha to new kombucha. into small building blocks—flavor comes from these building blocks (sugars and amino acids) and the things they break down and are transformed Things you definitely want to inoculate: into (see pages 9-15 on the flavors of fermentation.) So the thing you’re Koji, kombucha trying to make into miso should have starch and protein in it if you want it to taste good. Things we generally inoculate but can also grow spontaneously: Alcoholic yeast fermentations, acetic fermentations This book is just a guide—something that seemingly has the right characteristics for a fermentation might not actually work very well, but it’s difficult to Things we don’t generally inoculate because we get more interesting flavors know until you experiment. Different grains, for example, have the starchiness without inoculation, (but control what microbes can grow via the preceding and protein content that should make excellent koji, but their husks or the way methods): they take up and hold water might mean that the cooking technique you use for Lactofermentations, misos, shoyus, garums. pearl barley doesn’t work for, say, quinoa or buckwheat. It might take several tries to get something new to work. 98 · noma a field guide to fermentation · 99 Baker’s Percentages for Fermentation Overall Ingredient Percentages in Each Recipe Congratulations! You read all the recipes and understand how they work. If you have an odd amount of a base ingredient and know how to use baker’s per- Recipe Base centages you can scale each recipe to any weight using the proportions below. Lacto-fermentation Fruit, Ceps 98% Kombucha (Tea) Tea 82% Recipe Base Lacto-fermentation Fruit, Ceps 100% Kombucha (Tea) Tea 100% Kombucha (Juice) Vinegar Pea-so Rye-so/Nut-so Vegetable Shoyu Coffee Shoyu Garum Juice Juice Cooked yellow peas and some of their cooking water* Rye Bread, Nuts, Seeds, etc Vegetable Pulp Coffee Grounds VERY fresh squid trim, clam scraps, grasshoppers+ grubs, etc Additional Ingredients Calculate and Add 100% 100% 100% 100% 100% 100% 100% Salt 2% Kombucha (Juice) Juice 91% Sugar 12% Vinegar Juice 77% Old Kombucha 10% Pea-so Cooked yellow peas and some of their cooking water* 58% Rye-so/Nut-so Rye Bread, Nuts, Seeds, etc 38% Salt 2% Sugar 10% Old Kombucha 8% Old Kombucha 9% Apple Vinegar 15% High-Proof Alcohol 8% Barley Koji 38% Salt** 4% Barley Koji 26% Water* 32% Salt** 4% Koji 9% Salt 4% Koji 39% Water 49% Old Kombucha 10% Apple Vinegar 20% High-Proof Alcohol 9.60% Barley Koji 64% Salt** 8.30% Barley Koji 67% Water* 83% Salt** 6.50% Koji 10% Salt 2% Salt 4% Koji 10% Water 35% Salt 11% Koji 400% Water 500% Salt 20% Koji 22.5% Water 80% Salt 24% Vegetable Shoyu Coffee Shoyu Garum Vegetable Pulp Coffee Grounds VERY fresh squid trim, clam scraps, grasshoppers+ grubs, etc 87% 10% 44% * Water percentage approximate—water should be added to these recipes according to feel. ** For these recipes, calculate salt addition last, AFTER water additon. * Water additions for peaso, rye-so, nuts-so, etc. are best done by feel- these are just a guideline. ** For these recipes, it’s better to NOT use a baker’s percentage, add water by feel, and THEN add salt based on the final weight of base, koji, and water. 100 · noma a field guide to fermentation · 101 Notes 102 · noma Notes a field guide to fermentation · 103 Notes Appendix B The Tools of Fermentation 104 · noma a field guide to fermentation · 105 Oxygen control: vacuum bags, buckets, cloth lids, airlocks, and bubblers Passive barriers: clingfilm hats and cloth lids For miso and garum fermentations, it’s useful to protect the surface of the product from direct air contact, which can lead to mold growth. However, bet- As you may have gathered in reading sections on specific fermentations, con- ter flavor results if the fermenting mixture is not completely sealed off from trolling exposure to oxygen (removing it or encouraging it) is an important fac- air. Some of the fermentation processes seem to perform better if they’re not tor for doing a successful fermentation. Lactic and yeast fermentations should strictly anaerobic. Letting in some air also improves the flavor and prevents be protected from oxygen; miso and garum fermentations shouldn't be left solvent or nail-polish-like off-flavors, either by breaking down the ethyl ace- open to the atmosphere but shouldn't be totally oxygen-free (anaerobic), and tate that is responsible or letting it off-gas. For both of these we press clingfilm vinegar, kombucha, and koji fermentations need a plentiful supply of oxygen. onto the surface of the miso or garum as a kind of “hat,” but leave the edges loose. The tools we use for controlling exposure to oxygen for each fermentation are mentioned in their respective chapters. Here they will be discussed in more Any fermentation that gets airflow from the atmosphere needs to be protected detail. from fruit flies and errant mold spores by some kind of air-permeable lid. We cover misos, garums, kombuchas, and vinegar fermentations with a cloth se- Oxygen exclusion: vacuum bags and airlocks cured by a rubber band or string. A good way to prevent oxygen from reaching a fermentation is by removing it and then sealing the fermenting mixture. This is what we do with lactic fer- Active oxygenation: bubblers mentations, which are sealed with salt in a vacuum bag until the fermentation Acetic bacteria require oxygen to ferment alcohol into vinegar, and will grow is done. At this point, the bag will have swelled up with carbon dioxide gas, and ferment faster if they are supplied with lots of oxygen. To make a vinegar which is a byproduct of the fermentation process. This illustrates one limita- quickly, we circulate air into the fermentation. For volumes between 3-10 L, tion of vacuum bags: they are good at keeping what's in them contained, but we usually use an aquarium air pump and an airstone, which we buy from a they aren't good at letting gas out. pet store. These airstones use a pump to forces atmospheric air down a tube and through a porous stone, which makes tiny bubbles of the air and increases For fermentations that produce a very large amount of carbon dioxide, such the surface area exposed to oxygen of the liquid in which they are submerged. as alcoholic fermentations with yeast—which usually involve more sugar and For larger amounts of vinegar (up to 18 L), we use a dedicated vinegar ma- therefore more carbon dioxide—a device called an airlock is especially use- chine (which would be used for very small test batches in a commercial vine- ful. An airlock is a small, usually plastic device that is filled with water and gar brewery) which aerates the vinegar by forcing it through a small aperture seals a small opening in a bucket or jug holding a fermentation. As carbon di- called a venturi aspirator, which effectively increases the oxygen contact and oxide builds up, it increases in pressure, which is released by bubbling through fermentation speed of the vinegar mixture. the water in the airlock. The atmosphere on the other side can't push its way into the container through the water because it's at a lower pressure. So, oxygen-rich atmospheric air is kept out, carbon dioxide can be released, and the fermentation keeps going without mold growth or oxidation. 106 · noma a field guide to fermentation · 107 Humidity Lactofermentation: 20-30 °C Avoiding dry-out is generally more of an issue for fermentation and aging than Kombucha: 20-25°C removing humidity. For fermentation in a closed environment (like a wine Vinegar: 25-30°C fridge or disused freezer), keeping an open, full container of water near the Koji: 28-33°C heat source is usually good at maintaining humidity levels. If you have a ded- Miso: 28-33°C icated room for growing koji or aging misos or garums, a domestic humidifier Garum: 60°C can work well for the same purpose. We have used both of these strategies Yogurt and Creme Fraiche: 38-43°C effectively; in our current set-up we have a built-in humidification system that Cured Meats: 10-15°C has a humidity sensor and an ultrasonic fogger, which monitors levels itself Sake: 10-15°C and doesn’t need to be refilled but otherwise works like a fancy humidifier. Fruit Wines: 21-30°C if you're trying to extract color/tannins, 7-15°C for delicate, not very tannic ingredients If you have the luxury of being able to set humidity levels, the ranges you want Beer: 17-25°C for ale, 8-14°C for lager (warmer = fruity, banana, buttery off- to aim for are: flavors) Lactofermentation: 40-50% relative humidity Most of these temperatures fall somewhere in between refrigerator tempera- Kombucha: 50-60% relative humidity (to avoid excessive evaporation) tures (1-5°C) and temperatures you can reliably set ovens to (40°C plus). Note Vinegar: 50-60% relative humidity (to avoid excessive evaporation) that even though you can often set nicer combi ovens like a Rational to 30°C, Koji: 80-90% relative humidity the temperature will often spike a lot higher (40°C+) briefly during its heating Miso: 50-60% relative humidity (to avoid excessive evaporation) cycle, which can kill off the microbes you're trying to cultivate at 30°C. Garum: 65-70% relative humidity (to avoid excessive evaporation) Cured Meats: 70% relative humidity, with good air circulation If you're going to get serious about doing these fermentations, you will have a much easier and better time with some kind of accurate heat control. For this, we highly recommend using a PID temperature controller to control your heat Temperature control: PID boxes and heating sources source. A PID box is connected to an electrical power source, a temperature Keeping a precise, level temperature is important for controlling the rate of a sensor and a heat source. “PID” stands for “Proportional Integral Derivative” fermentation and what is growing in it, both of which have an important im- which means that the box uses calculus to figure out heating rate and heating pact on flavor. output (based on the readings it gets from the temperature sensor) and sends a certain amount of current through the heat source to keep a very stable tem- These are the working ranges for each of the processes in this book and others perature. Auber, Brainchild, and Eurotherm all make good PID boxes. you might want to do: For a heat source, you want something that can heat a fairly odd-shaped area pretty evenly. We have used heating blankets, seedling mats, and (most often) under-floor heating mesh for this. Under-floor heating mesh is sold in rolls to put down under a bathroom or other floor to heat it radiantly, and can be used 108 · noma a field guide to fermentation · 109 to line a styrofoam thermal box, an unplugged chest freezer or refrigerator, or almost any other container. You could theoretically make individual jackets, each controlled by PID box, for fermentation containers out of this. The heating wires that make up the mesh tend to get quite hot to the touch, so while the heat will spread through the air pretty evenly they can melt or soften temperature-sensitive materials like soft plastic or styrofoam when in direct contact. For larger rooms, we have had success wiring PID boxes to large infrared heating panels, which gently but effectively heat up an entire room. If they are ceiling-mounted and the flooring material is a dark material, this can cause heat to radiate from the floor and more evenly heat the room. Theoretically, a space heater could also be used to heat a room. Some PID boxes come with a standard plug-in connector for heating sources, but many need to be hard-wired (and floor heating mesh, wall mounted panels, etc. don't usually come wired with plugs). K-type thermocouples and RTD sensors are the most accessible and easy to find if the PID controller you have doesn't come with a sensor. RTD sensors are more accurate and thermocouples have a much wider working temperature range and are easier to wire, but the wire is fairly expensive. (Besides fermentation, you can do cool things with a PID box like put the thermocouple sensor inside a Green Egg grill, and use a fan pointed at the coals as a “heat source” to keep the grill at a stable 1000°C for a long time. If you want to try anything very high-temperature, use a thermocouple). Measuring sugar: refractometers and hydrometers For kombucha and yeast fermentations, you will need to measure sugar to make sure it is within the correct range for the amount of acidity or alcohol you ultimately want to reach. Glass Hydrometer: measures sugar by density. You fill a tall container (like a graduated cylinder) with the sample you want to measure, and gently drop the hydrometer, which is a long hollow glass piece with a wider, weighted bottom 110 · noma PID box schematic a field guide to fermentation · 111 and a thinner top with a measurement scale printed inside. The hydrometer If you need to take a lot of pH measurements, and especially if you need to will float higher in a more sugary solution, which is denser, than in a less sug- record pH measurements, buying a digital pH meter that connects to the ary solution, which is less dense. When it is floating evenly and not bobbing headphone jack of an iPhone/iPad is a good idea. We use a model called the up and down, you can read the specific gravity (density compared to water) SAM-1, which is produced by an American company called Sensorex. This runs or Brix (% dissolved sugars) at the line where the handle of the hydrometer about $200-250 for the iPhone adaptor and a spear-tip, double-junction (pro- emerges from the solution. These are inexpensive and don't require calibra- tein-safe) probe. This model can also email you a spreadsheet of readings from tion, but are easy to break and require large sample volumes to float in. your phone. Refractometer: measures sugar by refraction, or how much it bends light that passes through it. One version is a totally analog model, where you put a few drops of sample on an angled glass plate, close a cover over it, then hold it up to the light and read the brix from a scale visible through an eyepiece. These are less expensive than a digital meter, but usually only read up to 30-35 Brix and can be annoying to train someone to use properly. A digital refractometer (the Hanna company makes good ones) can be had for about $170 in the US, and will read accurately up to 85 Brix. To operate these, you drip a small amount of sample on a ~8-mm wide glass plate and press a button; it measures the refractive index and displays a Brix value. If you're going to do a lot of measuring this is a worthwhile investment. An analog model is slightly lighter and more portable if you plan on taking it to a farm or something like that. Measuring acidity: pH meters pH is an essential measurement of acidity for making kombucha, vinegar, and miso. The simplest and cheapest method for this is pH paper, which turns different colors according to pH which are then matched to a reference chart. This is not a terribly precise method, but is useful for a quick check and doesn't require calibration, though the color the paper turnsbecomes can be affected by the color of the sample. A digital pH meter is a worthwhile investment, and a small pen-style model usually runs $40-100. It should occasionally be calibrated using standard solutions, which will most likely also be sold from wherever you bought your pH meter (Amazon.com, lab supply company, homebrewing and winemaking shops, for example). For measuring the pH of miso, you should get something called a double-junction probe, as a standard pH meter will get proteins stuck to it in a way that can't be cleaned. 112 · noma a field guide to fermentation · 113 Notes 114 · noma Notes a field guide to fermentation · 115 Glossary acetic acid The acid that makes vinegar sour, produced from ethyl alcohol by acetic acid bacteria. amino acid A building block for proteins, which are folded-up long chains of amino acids. One amino acid in particular, glutamic acid (also called glutamate), is responsible for the sensation of umami taste: the richness in kelp, aged meats and cheese, tomatoes, and miso. We do fermentations like miso or garum where proteins get broken down into amino acids to create this umami flavor. amylase An enzyme that breaks down starch molecules into sugar molecules. Amylases play a big role in fermentation, for example in the malting process for making beer from starchy barley grains, and in the process of growing koji from Aspergillus oryzae spores on barley or rice grains. They are a powerful tool for making unfermentable ingredients more fermentable—for example, in making miso, the sugars that are created initially by the amylase in koji can then be fermented by lactic acid bacteria and salt-tolerant yeasts, creating complex flavors and preservation that wouldn't have been possible without this initial starch-digesting (amylytic) step. Aspergillus oryzae A mold originally from East Asia, which we use to make koji. We use koji for making miso, garum, shoyu, and koji water. Aspergillus oryzae converts starches into sugars and proteins into amino acids as part of its growth process and metabolism, and we take advantage of this and use koji to intentionally ferment carbohydrate- and protein-rich ingredients. backslop To inoculate a new fermentation by adding a finished, active fermentation to it. We make new vinegar by backslopping old vinegar into fresh, alcoholic liquid—the acetic bacteria living in the old vinegar grows in the new liquid and turns it all into vinegar. Some beer brewers will backslop yeast from a finished batch of beer into a new batch. bacteria Bacteria generally speaking are some of the oldest and most abundant organisms on earth, and unlike fungi and animal cells, are Prokaryotic (have no cell nuclei or other membrane-bound cell organelles), whereas fungi and animals are Eukaryotic (have their DNA inside nuclei, and specialized organelles inside the cell like the mitochondria, ribosomes, etc.) Bacteria we use for fermentation include lactic acid bacteria (LAB) and acetic acid bacteria (AAB). Both of these produce acids—LAB produce lactic acid from sugars, and AAAB produce acetic acid from alcohol. LAB are used to ferment sauerkraut, lacto fruits and mushrooms, koji water, and miso as well as yogurt, creme fraiche and cheese. AAB primarily ferment vinegar and kombucha and also create some acidity in misos. LAB can ferment and grow without oxygen (and many species prefer it) and AAB need oxygen to ferment and grow. carbohydrate A sugar or a molecule made of many sugar molecules linked together. Also called a saccharide— glucose is a monosaccharide, sucrose is a disaccharide, and starch and cellulose are polysaccharides. enzyme For the purposes of fermentation, an enzyme is a protein produced by a microbe to break down or chemically transform a molecule. For example, Aspergillus oryzae produces enzymes called proteases that break down a protein, which is a long chain of amino acids, into individual amino acids. Enzymes are usually named as "the thing they break down"+"ase" so, prote-ase breaks down proteins and amyl-ase breaks down starches (called "amylum" in Latin). More technically speaking, enzymes are produced in all living cells, and are the machinery that allows life to exist on a cellular level by catalyzing necessary bio-reactions that would otherwise happen very slowly or not at all. 116 · noma ferment Through fermentation we can make vinegar, kombucha, koji, miso, garum, sauerkraut, yogurt, beer, wine, and bread. We use "fermentation" generally to mean growing microbes in an ingredient and using their metabolic processes and enzymes to transform that ingredient. Very technically speaking, fermentation is also a metabolic process that releases energy from organic molecules (often, but not always, sugars) in the absence of oxygen. fungus The two fungi we use most often are Aspergillus oryzae (a mold, which converts starches into sugars and proteins into amino acids) for making koji, and Saccharomyces cerevisiae (a yeast, which converts sugars into ethyl alcohol) for making bread, wine, and beer. Mushrooms, molds, and yeasts are all types of fungus. Fungi can't photosynthesize their own food (as a plant would) and so they have to digest materials in their environment to get energy. To do this many of them produce enzymes which break down (technically speaking, they hydrolyze) molecules like starch, cellulose, and lignin. garum Historically, an ancient Greco-Roman condiment made from salted fish guts and innards allowed to ferment for months or years. The salt prevented the garum from spoiling, and the proteins in the fish were broken down by the proteases present in all cells and also in the fish's digestive tracts. We use the term garum to refer to any animal protein fermented enzymatically and with salt added, although we use the proteases in koji rather than in guts. inoculate You can kickstart a fermentation by adding a dose of the microbes you want to use at the beginning. Sometimes this means adding a pure culture—for example, a particular strain of yeast or spores from a specific mold. For some fermentations you can also add a little bit of a finished fermentation to a new one to inoculate it, such as adding old vinegar to a new batch of vinegar. This old-to-new inoculation is also called backslopping. inoculum The stuff you use to inoculate a fermentation. For example, a pure strain of yeast, pure koji spores, or old vinegar. koji Making koji lets us make miso, garum, and other complex, rich-tasting things from relatively simple starting ingredients. Koji is what you get when you grow the mold Aspergillus oryzae on steamed, cooled grains in a humid warm place for two days— the koji is the mold + the grains, which get bound together into a kind of slab or cake by the mold mycelium. Koji is rich in enzymes produced by the mold, especially amylase (which breaks starches down into sugars) and protease (which breaks protein down into free amino acids). These enzymes make the grains of the koji sweet and umami-tasting, and when you mix koji with another ingredient (like soybeans, which is how you make miso in Japan, or yellow peas, which is how we make miso here), they will also break down that ingredient's starches and proteins, creating fermentable sugars for yeasts and lactic acid bacteria to ferment, and umami flavors. lactic acid The sour acid in yogurt, sauerkraut, and other lacto-fermented products. It is an organic acid produced by lactic acid bacteria (LAB) from sugar, often in slightly salty environments. Producing lactic acid slows down the growth of other less acid-tolerant microbes which might cause spoilage, giving the lactic acid bacteria less competition and making fermented food safer for us to eat. lactic acid bacteria The bacteria we use for making sauerkraut, cultured dairy, lacto plums, etc. It's a group of bacteria that consume sugar and produce lactic acid as a waste product of their metabolism. Many species of Lactic Acid Bacteria (also abbreviated as LAB) are present on our skin and on the outside of plants, and will often begin fermenting plants, dairy, etc. without inoculation by a pure strain. The process a field guide to fermentation · 117 of intentionally using LAB to ferment sugars into acid is called lactofermentation, and is enhanced by adding small amounts of salt (2-8%) which LAB can tolerate but other microorganisms cannot, and removing oxygen, which stops spoilage by mold. lacto-fermentation Fermenting the sugars in an ingredient into lactic acid, using lactic acid bacteria. metabolism/metabolize The chemical transformations that an organism uses to live. Often this means that a cell getting energy from metabolizing one organic molecule into a different organic molecule. For example, yeast like Saccharomyces cerevisiae primarily get their energy from metabolizing sugar into ethyl alcohol, and lactic acid bacteria by metabolizing sugar into lactic acid. We take advantage of the metabolic processes of microbes to do lactofermentation and to make beer, vinegar, and koji. microbe Another name for a microorganism. microorganism A living organism that is microscopically small. We use microorganisms such as bacteria, yeasts, and molds for fermentation. Pretty much any surface that hasn't been very recently sterilized is covered in microorganisms, which are also found on our skin, in our intestines, in the soil, and pretty much everywhere else on earth. Yeasts and molds are both types of fungi which, like animal cells, have a separate nucleous holding DNA and various other separate structures called organelles that carry out the cell's reproductive and metabolic processes. Bacteria (like acetic bacteria and lactic bacteria) are an older, smaller, and simpler life-form with little internal structure, no organelles, and DNA floating around without a nucleus. miso A salty, umami-rich, sometimes sweet, sometimes tangy, sometimes very funky-smelling fermented paste from Japan made in two fermentation stages. In the first stage, steamed rice, barley, or soybeans are cooled and dusted with spores of Aspergillus oryzae mold, which is allowed to grow for about two days to make koji. The koji is mixed with boiled soybeans and salt and then left to ferment and age for 2 weeks to 2 years. Miso can also be thought of a process, and a template for transforming ingredients through fermentation. We borrow the technique of making miso and use Nordic ingredients—pearl barley in place of rice for the koji, and protein-rich yellow peas instead of soybeans to make Pea-so. mold A mold is a type of fungus. Molds form microscopic filaments called hyphae, with the mold cells themselves existing inside the hyphae. The interconnected network of hyphae that forms is called mycelium. The network of the mycelium will usually penetrate the material that the mold is using for food, and the mold cells produce enzymes that it secretes through the tips of the hyphae to break down and extract energy from the materials in its food source. The mold that we use the most is Aspergillus oryzae, for making koji. In koji, the mycelium looks like a fluffy white mat that holds the grains of rice or barley together. The mycelium eventually produces spores on the end of the hyphae, which makes it look extra-fluffy and sometimes green, and these spores can be used to inoculate or 'seed' another batch of koji. pH A measurement of acidity or alkalinity. The lower the pH, the more acidic something is— so pH is useful to know if you're relying on acidity as a preservative, for example in vinegar, lactofermentations, or kombucha. Acids have a pH lower than 7, pure water has a pH of 7, and alkaline substances have a pH above 7. Wine has a pH around 4, stomach acid about 1. A pH of 4 is 10 times as acidic as a pH of 5, and a pH of 3 is 10 times more acidic than a pH of 4. Technically pH is the negative log base 10 of hydronium ion concentration so pH 3 would have 0.001 moles of acid per liter. 118 · noma protease/proteolytic enzyme An enzyme that breaks down proteins into their amino acid building blocks. One of these, glutamic acid, is responsible for umami flavor. Aspergillus oryzae produces proteases that make miso, shoyu, and our garums rich in umami flavor. protein A molecule made from a long chain of chemically linked amino acids. Muscle fibers and enzymes are both made of different specialized proteins. Protein chains are folded into shapes that help them do their jobs and unfolding these shapes is what gives cooked eggs, meats, and cheese their harder texture. Individual amino acids, especially glutamic acid or glutamate, have a flavor called "umami" that we intentionally break down proteins with enzymes in miso and garum to develop. proteolysis The process of breaking down proteins (which are made from long chains or strings of linked amino acids) into individual free amino acids. This happens in miso and garum, because of the proteolytic enzymes produced by Aspegillus oryzae in koji. spore Like a seed for a fungus. We use Aspergillus oryzae to inoculate barley to make koji. The spore is a specialized cell that the fungus produces to spread itself to new locations once it starts running out of food in its current home. Spores are also called conidia, and are produced on stalks called conidiophores at the tips of the fibers called hyphae that molds build to live in. This makes it easy for the spores to be dispersed through the air. starch Found in grains, potatoes, etc. A molecule made of many glucose molecules linked together chemically in a long string or chain. Starch can be converted into sugar molecules by breaking these chains down, which is what Aspergillus oryzae does that makes it useful for fermentation. Starch is made from two different types of sugar chains, amylose (which is one long chain like a string) and amylopectin, which has many branched chains connected together (it looks like a tree branch or root). Amylose gets broken down more slowly by amylases than amylopectin does, and starches tend to be more sticky or waxy the more amylopectin they contain. substrate Substrate has different meanings depending on the context. For microbial growth and fermentation, it refers to the material that the microbes grow in and ferment. In the context of enzymes, the substrate is the molecule that is being modified or broken down by the enzyme (into a product or products.) sugar A sweet-tasting, soluble carbohydrate (also called a saccharide) that can bind to other sugar molecules in chains to make larger molecules. Glucose and fructose are important monosaccharides, and sucrose or table sugar is a disaccharide made from a glucose and a fructose bound together. Many microbes (lactic acid bacteria, yeasts) feed on sugars directly. Some other microbes (like Aspergillus oryzae mold) produce enzymes to break down polysaccharides into smaller sugar molecules. vinegar Vinegar is what you get when you ferment an alcoholic liquid (like wine, beer, cider, etc.) with acetic acid bacteria and give them lots of oxygen. yeast Yeast in a culinary sense usually means the species Saccharomyces cerevesiae, which is the microbe responsible for creating alcohol in beer and wine and making bread rise. Yeasts are a type of fungus, although unlike mold, they stay in single-cell form and don't make interconnected networks. Other yeasts you might encounter in fermented foods are Brettanomyces and Torula species, sometimes more broadly called "wild" yeasts. a field guide to fermentation · 119 Notes 120 · noma
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