Sandor Katz on Fermentation

In this interview, I talk with Sandor about fermentation techniques and success factors, interesting foods he's discovered in his travels, health, food safety, truth in advertising, some of the recent research into our microbiome, and many other topics.

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Michael: The New York Times called Sandor, “One of the unlikely rock stars of the American food scene.”


Michael: My guest today is Sandor Katz. He’s a James Beard award-winning author and lecturer. Sandor’s written five books on fermentation. I read your first one many years ago, and your Fermentation Journeys just fairly recently. So, I want to thank you for coming, and I especially want to thank you for just kind of all the love for fermentation and the interest that you put out in the world. You know, you started doing this long before it was a a “thing” or it was really popular; so you’ve really helped a lot of people get into this and kind of demystify the whole area of fermentation and eating fermented foods and gut health and all those things.

Sandor: Okay; well, thank you! Demystifying fermentation is my mission, so I’m happy to hear that thank you.

Michael: And by the way, I saw in your latest book a recipe for sauerkraut chocolate cake.

Sandor: Sure, that’s a thing. You can make delicious chocolate cake using sauerkraut, and nobody will know that there’s sauerkraut in it unless you tell them. It just functions as a moisturizer, keeps the cake moist, and also, the acidity of it will help rise the cake reacting with baking soda.

Michael: Yeah, it’s interesting — my son and I, a while ago, made pastrami, and we made bread and everything, and then we made Reuben sandwiches, and we used kimchi in the sandwiches (that my wife had made), and it was delicious! And like you say, you don’t really taste the kimchi in there. It just really elevates the taste of the sandwich. It’s super interesting.

Sandor: Yeah. Fermented vegetables are incredible condiments and like —a little bit can go a long way in making the sandwich or the food that you’re eating it with more delicious.

Michael: So I wanted to just start by sort of defining fermentation. In my class, I give three different definition of fermentation starting with the very scientific, but I really like your definition of fermentation for just kind of broad discussions about food and health and nutrition, so I just wondered if you would talk about that a bit.

Sandor: Great! Sure, so generally, the definition of fermentation that I work with is that fermentation is the transformative action of microorganisms. Generally, scientists would understand it to be anerobic metabolism, and in fact most of the foods and beverages that we describe as fermented are the results of anerobic microbial processes, but not all of them; so I just like to work with this more expansive, broader definition of fermentation, but it’s also important to acknowledge that not every microbial transformation results in something delicious that we want to put into our mouths, and so really the definition of fermentation is the intentional or the desirable transformative action of microorganisms.

Michael: Right; and there are some foods that we may not want to put in our mouths but other people might. That’s one of the interesting things in your book. I’ve made natto before, which a lot of westerners probably wouldn’t want to try, but in Japan it’s very popular.

Sandor: Certainly there’s a there’s a large degree of a cultural subjectivity, like what people are used to, and I think that we don’t have to look any further than cheese to see that, and my taste has evolved over the course of my life. I love strong, stinky cheeses, and if 10-year-old me could see what 60-year-old me likes to eat, 10-year-old me would be profoundly disturbed. And so, even in in the course of my lifetime the idea of what flavors are acceptable and what flavors are desirable has changed. And, of course, now and then I invite some friends over, and I have some nice some cheese that’s nice to me and inevitably somebody will say, “did something die in your kitchen?” And a smell like that would be nothing that they would be comfortable with as food, so no, there’s a high degree of subjectivity as to what is desirable and what is acceptable to eat, but a lot of the foods at the edges of that are products of fermentation and fermentation creates a lot of edgy flavors as well as textures, as you point out with natto.

Michael: Are there fermented foods — I know you’ve traveled all over the world and tried all kinds of stuff — that you won’t try or you’ve tried and they’re just like, “no this is definitely not for me.”

Sandor: I mean, not really: not traditional fermented foods, no. I mean, certainly I’ve had individual people with their experiments at home say, “Oh this smells really foul; I’m afraid to taste it.” And sometimes it is, and sometimes when they tell me the story of how they’ve made what they’ve made I can tell them exactly what the problem is. I mean, certain foods have toxins in them that taste awful, and in certain cases those can be reduced by fermentation, but not in every case. Sometimes there’s very specific parameters for safety, and we have to regard fermentation first and foremost as a strategy for safety. If you’re able to preserve food or create incredible flavors and 80% of the time it’s safe to eat, you know, that’s not very reassuring, so the process has to be safe, and let’s say — you know, one ingredient that’s often put into cured meats for the sake of safety are nitrite and nitrate, and so occasionally I’ve had people say like, “Look, I made my salami without using any nitrate or nitrate. I want to give you a slice!” And I’m reluctant to taste things like that because the nitrate and nitrate are really in there for reasons that I find extremely compelling for safety; so I haven’t tasted everything that anyone’s handed to me. Occasionally there have been things I’ve tasted and disliked, but generally I find the flavors of fermentation wonderful, and as long as I can watch somebody taking pleasure in it, then I’m really game to try it myself, and I I’ve never gotten sick. Some of it’s been more delicious than others, but I’ve never found anything that was terrible.

Michael: And that brings up a good point. There are certain ferments like natto that we talked about where you do have to be really careful in the process of how you make it, and then there are other ferments like sauerkraut or pickles that it’s kind of hard to screw up in terms of health and food safety.

Sandor: I mean, fermented vegetables is about as safe as food gets. It is safer statistically speaking to eat vegetables that have been fermented than to eat raw vegetables. The fermentation makes the vegetables safer, so there’s absolutely nothing to be concerned about in the fermentation of vegetables — or, I would say, in any raw plant materials. Once we start getting into higher protein substrates that are more — let’s say intrinsically dangerous — fermentation still makes them safer, but there are case histories of illness in relation to fermented cheeses, fermented meat, or fish products, so the fermentation still makes them safer, but it’s really important to understand the parameters for safety: what kind of conditions are you trying to create? And that’s what fermentation is really all about is creating conditions, manipulating environmental conditions such as access to air, temperature, pH, things like that, but creating conditions that have the effect of encouraging the growth of certain kinds of organisms that are desirable and simultaneously discouraging the growth of other kinds of organisms which might be less desirable, and the reality is that everything we eat — all of the plants, all of the animal products, everything that we eat, is populated by microorganisms, and never one single organism — always these broad communities of organisms — so really, the big question is: which ones are going to grow? And that’s really a function of environmental conditions, and that’s why it’s really important to understand what conditions you’re trying to create.

Michael: And that’s an important point you bring up as well that in — I don’t remember which one of your books, probably all of them — you talk about how you eating a monoculture of bacteria (like a pack of yeast, for example) is so different healthwise and taste-wise as well from this community of bacteria and fungi and so forth that you get when you do wild fermentation.

Sandor: Yeah, sure. I mean, the idea of a singular microorganism is a very recent idea in the scheme of things — like the idea of yeast as a separate thing that you would add to your bread — I mean, that pretty much became available only in the 20th century, and so people have been making bread for something like 10,000 years, and all of the bread for the first 9,900 years involved a mixed culture of the organisms that you find on wheat, on rye, on millet, on sorghum, on any kind of a grain, and so that’ll always involve yeast. But it’ll also involve lactic acid bacteria and other bacteria, and so today many people make bread with some sort of a sourdough starter, and there there’s yeast in there but it’s not yeast alone, it’s yeast in the company of all these other bacteria, and these bacteria play an important role too, especially in the nutrition and in the flavor of the loaf that results, so the lactic acid bacteria, well, they’ll make it a little bit more acidic —depending on the technique you use it could be a little or it could be a lot — they’ll break down gluten, so the resulting bread can have a lot less gluten in it if you used a mixed culture, natural fermentation. Also in terms of nutrient bioavailability, the minerals that are part of all grains are tied up in these chemical bonds that our bodies generally can’t break down, but lactic acid bacteria can. So, it actually makes minerals more bioavailable. So there are all these ways that the bread can be improved by the broader group of organisms as compared to just using the single organism of modern industrial bread-making.

Michael: Right. And you talk about how, going back to many thousands of years ago, with how we would do ferments like bread — it’s really interesting, starting with symbiogenesis, and just our inter-dependence on bacteria from basically the beginning of eukaryotic life, right? — both within the cell structure, but also our inter-dependence of it. I read a few years ago about human milk oligosaccharides, and it’s fascinating how mothers are basically producing prebiotics for their babies in the breast milk. It’s just crazy how integrated our biology is with bacteria.

Sandor: Sure. I mean, these systems that produce us and sustain us are complex, and there’s a broad consensus in evolutionary biology that we and all multicellular forms of life are evolved from simpler, single-cell forms of life: prokaryotes, like bacteria and archea. And the flip side of this, that doesn’t get talked about as much, is that all of the multicellular forms of life live with these communities of bacteria and other single cell organisms that are simply part of us and part of our ability to function and so, in the case of our human bodies each of us is host to, I don’t know, mindboggling numbers — more than a trillion bacteria that give us various aspects of our functionality, and when babies are born, that’s one of the most immediate, most urgent needs that they have is to become populated. And this begins during birth: they’re populated by bacteria that are in their mother’s bodies [and] on their mother’s bodies. As they feed off their mother’s milk, they’re gaining bacteria. As they begin to explore the world by sticking everything into their mouths, they are diversifying the bacteria in their bodies, and then in the end, those bacteria help the baby develop an immune system, help enable it to effectively digest food, and assimilate nutrients. And, you know, it turns out that every aspect of our physiology relates to bacteria. We’re learning in recent years that some of our brain chemistry — serotonin and other chemical compounds that determine how we feel and how we think — are regulated by bacteria in the gut. So, you know the bacteria are just related to every aspect of our functionality. And basically, since the discovery of bacteria in the late 19th century, in the popular imagination they became associated primarily with disease and death, but — and, you know, we can’t deny that there are a relatively small handful of bacteria that can make us sick or even kill us, but I would say that the bigger picture the bigger reality is that we can’t live without bacteria, and bacteria are the matrix for all life, and fermented foods are a way that people in every part of the world learned to deal with this reality: that all life has bacteria on it. The people who figured these things out didn’t even know about bacteria, and yet they were able to observe that under these conditions the food decomposes, and under these conditions the food is elevated, and there’s always a practical benefit to fermentation. Either you’re producing alcohol, you’re making food more digestible, you’re preserving food, you’re removing some kind of a toxic compound from the food, you’re making it more digestible, … there’s just always practical benefits to — oh, we can’t forget flavor! You’re making it taste more exciting.

Michael: Yeah, the whole concept of the brain-gut axis and what we’re learning about this connection, like you were just mentioning, between not only health, but mood and other things that is directly from the bacteria that we have, and what colonies of bacteria — you mentioned childbirth is part of creating our initial colonies, and I know that babies who are born via C-section have certain health issues that — because they’re not exposed to that bacteria during childbirth. Right?

Sandor: Yeah, yeah, absolutely. And I know that in some places people have developed protocols for babies who are born by C-section to try to expose them to some of the bacteria that they would have been exposed to if they had been born the traditional way.

Michael: There’s also definitely been a fermented foods have become so popular in just in terms of nutrition and health and the general public perception of them — lots of companies have sort of jumped on this bandwagon. There’s a tea company that I saw advertises that they have Bacillus subtilis spores in their tea that they claim get through the brewing process everything and get into the gut and have health benefits and there are companies that basically make their own strains of bacteria and name them and put them in their products. So, I’m just curious — and some of those don’t —I think the health benefits — the colonies may not even survive all the way through the best-by date on the product, so how does a consumer sort of navigate this this very complicated array of — making their own things or just looking for something that’s says it’s raw with live cultures. Or, what are the things they should really pay attention to and how do they figure it out?

Sandor: Well, I would just point out that products of fermentation have enjoyed enduring popularity, and in our great-grandparents time, fermentation was no less economically important than it is today. If you think of all bread being fermented, all cheese being fermented, all cured meats being fermented, vinegar being fermented, all the condiments being based on vinegar, … so, fermentation is not just suddenly now-popular. What’s new is that people are thinking a lot about fermentation. Like, if you’re buying bread in 1920, you don’t have to be thinking about fermentation. If you’re buying bread in 2024, you don’t have to be thinking about fermentation, but it’s still fermented. Now, in terms of like — when anyone’s got a proprietary bacteria in anything, that’s a red flag. We don’t need proprietary strains of bacteria, we just need biodiversity. And so, I mean, personally as a consumer, I am completely unswayed by products that are promoting some particular super strain that they have, and in fact that will push me away to a different kind of product. I mean, I want to encourage people to not dismiss the idea of making it yourself. Certain things — especially like fermenting vegetables — are just incredibly straightforward and simple to ferment yourself. Like, to make sauerkraut you chop up vegetables, lightly salt them to taste, add other seasonings if you like, spend about 5 minutes squeezing the vegetables — that breaks down cell walls and gets them juicy. Once they’re juicy, you pack them into a vessel which can be as simple as a jar like this [shows] and ferment. A quart jar will take about 2 pounds of vegetables, so, I mean, it’s very simple to do, and then you wait —there’s no fixed amount of time — somewhere between five days and several weeks depending on how strong you like it and depending on the temperature of your environment. The higher the temperature, the faster the metabolism of all these organisms, and, of course, the acids accumulate over time, and some people like it stronger, more sour, and some people prefer it milder, before it reaches that that level of acidity. So you can make them yourselves — or what my preference is, is to search for locally produced products, and with locally produced products, it’s usually easy to reach the people who are making them, whether you’re talking to them at the farmer’s market or reading their label, calling them, looking at their website, … but you want foods that are produced in simple ways. Generally, the foods that are alive — if they’re in a market — you’re going to be buying them out of a refrigerator rather than on a room-temperature shelf. It could preserve at room temperature, but it’ll build up pressure [in the jar], so once you once you seal it in a jar, effectively it needs to be refrigerated. So that’s where you’ll find it in a store. So, those would be my basic guidelines of what to look for when manufacturers start making specific health claims about specific foods. For me that’s a red flag. I mean, sauerkraut can have profound benefits, but when people start telling me that sauerkraut is going to cure cancer and, you know, make me thin and solve all of my other problems… I don’t know. I mean, I just think that it’s inappropriate for a food manufacturer to make specific claims. Food can be profound medicine but individual foods do not cure disease. It’spart of a bigger picture of your whole diet.

Michael: you mentioned making sauerkraut and salting the food and one thing I learned from your first book, which surprised me at the time, is that short-of inhibiting the pectinase, just in terms of the texture of the food, you don’t actually need salt to do a ferment, right? So for people on a low-salt diet, it’s not a necessary part of the process

Sandor: I mean, my advice would be low salt I mean, the salt really enhances the flavor, and the salt really enhances the texture, so we all need salt, and so, if you’re concerned about salt — if you’re trying to avoid eating salty food (that is, very salty), you can make it with exceedingly small amounts of salt, but it’ll always be better with a little bit of salt than with no salt. But, absolutely, there are, in the world, conditions where people ferment vegetables without any salt at all, and salt is not the thing that makes it safe. The thing that makes it safe is lactic acid bacteria, and once you get vegetables submerged — which is easier to do with salt then without salt — but once you do that, then lactic acid bacteria will dominate every single time and that’s what’s keeping the vegetables safe. You’ve referred a couple times to my first book, so let me just show it: it’s Wild Fermentation. I also have a book called The Art of Fermentation; and then my most recent book is Fermentation Journeys.

Michael: I think your latest book — whether you’re interested in fermentation or not — it’s just such an interesting exploration of cultures and eating around the world. I think it’s just fascinating for anyone to read just from that aspect — and not to mention just getting ideas of things that they might want to try in recipes. It’s a beautiful book.

Sandor: Well, thank you, thank you. I mean the reality is — and I mean, I’m learning more and more about this — but in every part of the world, people use fermentation. It’s just an essential part of how people make effective use of food resources and the ways that people work with fermentation are very different in different parts of the world, but there are definitely repeated patterns that come up, so I’ve learned so much by traveling. And a few weeks ago I was visiting Korea, so now I’m kind of like obsessed with Korean food in general but especially Korean fermentation. So, I’ve been doing a lot of Korean-style fermentation lately.

Michael: What, speaking of Korea, aside from kimchi — what foods have you found there that you love or think are really interesting or people should try?

Sandor: Well, one thing is that the flavors underlying Korean cuisine are largely driven by their particular methods of fermenting soybeans. So, in Korea, after the soybean Harvest, many of the soybeans are soaked, steamed, crushed, and turned into these blocks that look like bricks, and then they’re partially dried — generally in contact with rice straw, which really drives the fermentation and introduces the fermentation organisms to the block of cooked soybeans, and then they’ll hang it, tying each one up with straw and hang them for a month and a half to three months, and then take those blocks and put them in vessels with a salt strong saltwater brine, like a 10% brine, and then that’s the source of both their soy sauce and their soy paste, so the soy paste is doenjang, the soy sauce is ganjang, and so after a couple of months of fermentation in the vessel, they separate the solids from the liquids, put the liquid in one vessel [and] the solids in another vessel, and continue fermenting them, and the flavors of the soy fermentation really just infuse everything in Korean cuisine. And then of course there’s kimchi — it is a whole other thing, and kimchi is not just one thing people eat at a given meal. People might serve two or three different kinds of kimchi, and there’s lots of different styles of kimchi, so I’ve been having fun for years experimenting with different styles of kimchi. It’s not all super spicy. Some of it doesn’t have any chili in it at all. And then you mentioned natto. There’s cheonggukjang, which is very similar to natto. In its bacterial analysis, it’s the same bacteria: Bacillus subtilis. The characteristic aroma of it — but it’s used in in ways that are very different from the way they’re using it in Japanese cuisine, in that it’s mostly cooked and the basis of stews and things like that. So, there’s a lot of different ways that fermentation is used in Korean cuisine. There’s also a whole category of fermented seafood — you know, fermented squid, fermented pollock roe, fermented shrimp, lots of different kinds of fermented seafood. So, there’s really quite a lot of different kinds of fermentations going on in in in Korean cuisine. Also, this amazing fermented rice uh soft drink sikhye — so delicious, so, so wonderful. So, everywhere in the world fermentation is used in the cuisine in a variety of different ways.

Michael: Is there anything on the science side of fermentation that you’ve read or looked into recently that you found really interesting?

Sandor: To me the interesting thing is that science is just beginning to understand fermentation. Until the time when I first got obsessed with fermentation, which is a little more than 30 years ago, science had not developed ways to understand large communities of bacteria, so everything was based on what we would understand about singular microorganisms. But the limitation of that is that’s not how microorganisms exist in the world. Microorganisms always exist in the world in these broad dynamic communities where the organisms are interacting with each other, so it’s literally in the last — really since the new millennium  that science has been developing ways to look at bacterial communities, and so we’re beginning to have a better sense of the diversity that exists within our bodies. But we have a lot to learn about the dynamics of the interaction among these organisms and the same in any kind of a given fermented food. So we can do a PCR analysis of a food at a given at a given moment and get a sense of the diversity of organisms that exist within it, but does that tell us if something different is happening near the top where there’s more oxygen than at the bottom? What’s happening in the first hours of fermentation when all the ingredients are put together? But there’s all of these things we don’t know, and I think that what’s really important for people to understand is that the science of microbiology is in its infancy and we have learned some things, but the more we learn the more we realize we don’t know — so, I think we have to understand microbiology to still be really in its infancy.

Michael: You mentioned the —near the top — I’m curious are there microaerophiles that are an important part of fermentation that you know of? Are there different types of species in terms of their oxygen needs that are part of this community?

Sandor: I mean certainly there are there are some organisms of fermentation that require oxygen so like if you want to make vinegar — that requires oxygen. Acetobacter always require oxygen, so the best way to protect a fermented alcoholic beverage from turning into vinegar is to have a full bottle and keep it well sealed, so that there’s no access to oxygen. Once you let oxygen in, it’ll start to turn to vinegar. And if you want to turn it efficiently into vinegar you want to have a broad surface area so there’s a lot of oxygen contact. The solid-state mold fermentations I talked a little bit about — soy sauce and soy paste — well those are both based on — in the Korean example it’s meju. In China it’s called qu. In Japan it’s called Koji, and Koji is the word that has become famous around the world. But these fungi that have been very important in Asian Cuisines for thousands of years. They are aerobic organisms, and so they always need access to oxygen. And I actually just had a researcher from Spain get in touch with me. It turns out that there was a seasoning that was ubiquitous in southern Europe up until the Middle Ages that involved growing molds, and this researcher had just found these historic documents that describe this food and the method of its production. I can’t even tell you the name of it right now, actually, but certain foods rely on oxygen. But in terms of organisms flying through the air, I mean, that’s always going to be an influence, but a relatively small influence compared to the organisms on the food that you’re fermenting, the organisms on your hands, … very often botanical ingredients will be used with something that’s cooked — like I mentioned the Korean soybean blocks meju, it’s always rice straw: everyone I talked to about it talked about the importance of rice straw, so the straw from growing rice turns out to be an important vehicle for introducing the right fungus onto the cooked soybeans.

Michael: Are there any — in your travels — anything that’s really surprised you or things that you think are really interesting?

Sandor: Well, sure. I mean, you brought up natto, and natto is something that’s really of interest to me. Natto is a Japanese name for a Japanese food, but what I’ve been learning slowly over the course of many years is foods just, well — first of all, the bacteria that produces natto. Bacillus subtilis is one of the most common soil bacteria everywhere. We are all eating foods with Bacillus subtilis on it all the time, and the Japanese are not the only culture that have made use of it. I mentioned that there’s a Korean similar kind of food, and in Thailand and Burma there’s a similar kind of a food. I, in China, saw a similar kind of a food. In the northeast of India in Nagaland there’s a similar kind of a food. They all have different names. In most of the places other than Japan it’s dried. So, like, in Thailand and Burma you’ll find these little dried discs that you can buy in the market. It’s basically fermented soybeans mixed with some spices — turned into a little disc and dried so it becomes stable, and people use it as a seasoning. Then all across West Africa people use seasonings — not based on soybeans, but based on African Locust beans: beans that are indigenous to there, but it’s the same bacteria Bacillus subtilis. It’s the same characteristic aroma that it has, and in West Africa as well, it’s typically dried. Dawadawa is the Yoruba name for it. There’s lots of different names for it: iru, sumbala, … more names than I than I know, because there’s so many different languages and cultures that are using foods like this. But it turns out that this the flavor of natto — which has maybe scared so many Americans if they tasted it in a Japanese restaurant without knowing what it was — is actually a flavor that underly underlies food in a lot of different places where used as a seasoning. And what I what I do in my own kitchen is I dehydrate natto, and I grind it up with sesame seeds and salt. And I just this morning I had some eggs for breakfast and I put this little seasoning on my eggs. And so, it’s really widespread around the world. So, sometimes in my travels I see things that are just completely unique that I’ve never seen anywhere else, but also I get to see repeated patterns, because, of course, fermentation is driven by soil microbiology, and it’s not completely different, what kind of organisms you find in the soil on one continent versus another. There are large similarities and patterns of similarity.

Michael: You mentioned Bacillus subtilis — I’ve seen the specific natto strain of that bacteria. Is that important for making natto? Does it change the flavor or anything, or is that just a way of selling a particular thing where really, like you mentioned, it’s so prevalent that it’s probably a little easier to get a hold of.

Sandor: Well, I mean, the easiest Bacillus subtilis to get a hold of is: you dig a hole anywhere in the world and it’s on the soil, and it’s on the beans, and it survives boiling. But Bacillus subtilis var natto — it’s a specific strain. It produces very specific flavor. It produces very heavy mucilage, stringiness. A lot of the wild strains of Bacillus subtilis will produce a similar aroma and flavor but not as luxurious of a stringiness. But, I was told repeatedly in my visit to Korea when I would bring up cheonggukjang, which is the Korean equivalent of natto, people really felt like it’s very different from natto because natto is always made with a specific strain, and the Korean one is typically wild fermentation, just based on what’s on the beans. But to me, it smells the same and sometimes it’s more stringy; sometimes it’s less stringy. I mean, you get —the thing about starter cultures, and, you know, we talked about yeast — you can buy Bacillus subtilis var natto. I mean you can buy starter cultures for lots of different kinds of things but they’re all departures from the history, and it happens that Japan embraced the science of microbiology very early, and most of the Japanese ferments are made from specific starters, and, I mean, I don’t think anything is wrong with that, but I do think it’s important to acknowledge that it’s a departure from the traditional ways that people have made fermented foods which have been using the organisms that are that are on the food. Or, there there’s another method of “backslopping,” so with my sourdough starter, I’m not starting from scratch every single time. I just make sure I never use all of my starter, and then I keep feeding it more flour and water, but the backslop means that there’s some of the original bit in there that I’m mixing with fresh flour and water in order to perpetuate it. And that’s how that’s how yogurt works. This is the yogurt that I make, and I’ve been using the same culture for years and years, and I just I try to never eat it all. I always leave a jar to use as the starter for the next batch of yogurt. So, well, that was a rambling answer.

Michael: No, that was great. I wish we had a little more time because I would like to ask you also about like the reusing of certain — backslopping with certain things. I’ve read that you can do them a certain number of times, but after that you should start again with a fresh batch of, like, commercial starter or something.

Sandor: Like with what?

Michael: Like with yogurt, for example.

Sandor: Well, okay. That’s only if you’re if you’re using commercial yogurt. It’s not made from a traditional starter, it’s made from a couple of pure culture lines. If you can get ahold of an heirloom yogurt culture, it should it should be able to go for years and years — generations and generations — and of course, things can go wrong. You always want to have like a plan B a backup, like a neighbor who’s also making yogurt — something like that. But in general, like most tradition, I mean…. I could tell you a little bit about why pure culture starters can’t sustain themselves over time, but we wouldn’t know what this food “yogurt” was if there weren’t traditional cultures that were really able to effectively maintain themselves over time. And the fact is, the biodiversity of the traditional starter is what gives them that ability to sustain themselves over time. They have sort-of like a — we could call it a defense strategy. They have the ability to defend themselves over time from random bacterial exposure and from phages [bacteriophages]. Phages are viruses that effectively constitute diseases for bacteria, and so a really good strong yogurt starter is able to protect itself from random bacterial exposure and from phages over time in ways that pure culture starters just never can.

Michael: Well, I super appreciate your time. Are there any last comments you want to make before we wrap up?

Sandor: Well, let me just tell people that have a website You can find information about my different books on there. And I do a lot of teaching. You can find out where I’m teaching. Some of that teaching is online some of it is in particular places, so my website is where you can find out about it. But my parting words are: don’t be intimidated. People have been fermenting in kitchens that are much more basic than yours for thousands of years, and if you’re at all interested, don’t be intimidated. Don’t be afraid. Jump in!

Michael: Well, thank you so much, Sandor. This has been really great. I again appreciate your time.



Sandor Ellix Katz

Wild Fermentation

James Beard Award-winning author Sandor Ellix Katz is a fermentation revivalist. His books include: Wild Fermentation; The Art of Fermentation; The Revolution Will Not Be Microwaved; Fermentation as Metaphor; and his latest, Fermentation Journeys. These books — and the hundreds of fermentation workshops he has taught around the world — have helped to catalyze a broad revival of the fermentation arts. Sandor is a self-taught experimentalist who lives in rural Tennessee. He has received many honors for his work, and the New York Times called him “one of the unlikely rock stars of the American food scene.”