David Zilber // "The Noma Guide to Fermentation" book cover
Photograph by Evan Sung // Illustration by Paula Troxler

Noma's Fermentation Genius is No Stranger to Bad Smells

We talked to David Zilber about what you might do with salmon kombucha and why everyone should start fermenting.

David Zilber is not willing to issue a death certificate for our SCOBY, whom we’ve named “René,” yet. Our kitchen is a little cold, and René’s microbes might just be working slowly to turn the sugar in our sweetened coffee into alcohol, and the alcohol into acetic acid.

“It’s really hard to come into a ferment halfway, be with it for five minutes, and diagnose if it’s alive or not,” he says, surveying the floating raft of microbes. But what should be coffee kombucha is definitely missing its characteristic tang. Sometimes, that’s how fermenting goes—Zilber describes his job as being a “shepherd” for the living organisms that ultimately transform the starting ingredients. Environmental factors contribute heavily to the process, so even though it’s a fairly exact science on some levels, the end results can still be surprising. Zilber’s new book, The Noma Guide to Fermentation, written with SCOBY namesake René Redzepi, manages to straddle that dichotomy, providing both a granular account of the various microbes and potential pathogens while also detailing the philosophical appeal of fermentation and describing grasshopper garum as a “magical ferment.”


The recipes themselves are often simple, and Zilber assures us that there’s nothing omitted for proprietary reasons. The magic is harnessing the microbes. So even if it takes a little longer for our sleepy SCOBY to do its thing, eventually we’ll have the same coffee kombucha that’s served at Noma, and possibly everywhere else soon if Zilber gets his way.“ Starbucks is going to start serving this is in two weeks,” Zilber says.

We talked to him about fermentation, salmon kombucha, and how he got to be leading one of the most interesting spaces in food.

MAKE THIS: Coffee Kombucha

MUNCHIES: Hi, David. How did you end up at Noma?

David Zilber: Well, I think every cook in the world has a restaurant that they aspire to work at. And for me, that was Noma. I was working at Hawksworth restaurant in Vancouver, which had the prestige of being Canada’s best restaurant, [but] no one outside of Canada has heard of it. I put in my time there, I was a sous-chef, I was running the dinner service. So it’s like, you made it and then you’re like, “Well, where else can I go?” You get offers to open your own restaurant. And I could do that and struggle, or I could be over-prepared and go somewhere better to learn more. I had never worked at a Michelin-starred restaurant because there are no Michelin-starred restaurants in Canada, so you kind of don’t know your worth, in a way. I wrote to Alinea, Saison, and Noma, and Noma was the only one to get back to me.


Well, that’s not so bad.

So I hopped over there, started working, and about a year into my time at Noma, they sat me down and told me that the lab team wanted me to join them.

I imagine that meant moving off day-to-day cooking. Were you at all ambivalent? Or just excited?

Yeah, you stop being a cook and you start doing something very different. I wasn’t at all ambivalent. I was a bit shocked. I didn’t see it coming. I was shocked at the offer initially, because I wasn’t a gung ho fermenter. You’re so busy in the kitchen—you have to do everything. But I realized it was a moment in my life where, like, oh, this is one of those forks. This is one of those life-defining yes-or-nos. And then I said yes, because I knew it was too amazing an opportunity—too rare an opportunity—to pass up.

What was your experience with fermentation before that?

Pretty much the standard, same as anyone else: You pickle some shit. You make sauerkraut and kimchi a couple times for a new dish you want to try out, and it’s like, “Oh, cool.” But you also have to worry about ordering, and catering the banquet you’re doing. As a regular chef, it’s hard to get the time to do pure [research and development] and discover stuff that no one else has discovered.

What do you do, day-to-day, in a fermentation lab? Before you started the book, what was your job like?

There was no standard day. It could constitute everything from writing recipes for the restaurant—which is part of my job as well—to doing R&D, which is like, “Oh, there’s this cool ingredient and this is what it tastes like raw, maybe we should do a lacto-ferment, maybe we should juice it and try the vinegar;” to reading a research paper and being like, “there’s a long term project we really want to get on and what would it take to get that;” to just keeping up with production. Because while we’re an R&D facility that’s equipped to come up with this shit, once we do, it’s like, “Who else is going to make it?” Of course it’s us. So we also have to produce it. That’s a fair bit of our time, depending on the menu and how heavily ferments are being employed.


What was the learning curve like to become a fermentation expert?

My predecessors taught me well: Lars Williams, who’s now at Empirical Spirits, and Arielle Johnson, who is at the MIT media lab now. They were the team that built the first fermentation lab. And when I was brought on board, Lars is a great teacher and he taught me the ins and outs. And it’s amazing because it’s not like he’s a master, and it’s not like I’m a master. So, in instances we would have to troubleshoot things together.

What do you mean, not a master?

Like, he taught me how to make koji. But then the koji would go wrong. And it’s like, “Oh, it’s off. How come it’s black inside?” And this is your teacher not understanding something. But that’s incredibly empowering. It lifts you up. Because it’s like, all of a sudden it’s not like, if he doesn’t know no one knows. It’s like, “This is on us to figure out together.”

Do you feel like you’re still learning?

Absolutely. I wish I had more time to learn.

What would you want to learn about?

Everything else. Everything. OK, so you have ingredients. And you can enjoy them raw, you can enjoy them cooked. You think about a filet of salmon, and everything you can do to it to transform it into every version of salmon that has ever been created on earth. Cedar-smoked on the barbecue, cured into gravlax, pureed into mousse, steamed, pan-roasted, grilled, broiled. You understand that cooking is an infinite spectrum of things that become other things. And there is one subset of that that is fermentation, and that’s its own infinite world in and of itself. And you could say, “Sure, you can ferment salmon.” But then you go down that rabbit hole and fall into Wonderland. How can I ferment salmon? What microbes can I use? And then it becomes this other advancement. And it’s equally as vast as cooking.


So, walk me through that. If you were in the fermentation lab at Noma and you just wanted to do salmon somehow , what would be the consideration? If you have a new ingredient, how do you decide what to do with it?

Well, you look at what it is, and then you put that through the appropriate lens. So fermentation has a lot of different worlds of fermentation, if you will. And depending on your starting material, some worlds will be better than others. Sure, you could make a stock of salmon, and sweeten it with maybe fennel juice, and make this salmon kombucha. You could do that. But it might taste a little weird. And what would you use it for? You definitely don’t want to drink it.

So OK, that’s for a salmon fish soup that tastes like it’s been sitting out for a few days. But then garum—has anyone made a fish sauce from salmon before? No? Cool. Let’s try that. You chop up salmon and you make this incredibly fatty, rich, oily fish sauce that hasn’t been made before and it’s probably going to taste very different from the fish sauce that’s made of anchovies in Thailand. And all of a sudden you’ve created this new thing.

So what are some of the more outlandish things you’ve tried to ferment?

Pigs’ blood. It stinks. I tried it; it’s disgusting.

How did you try to ferment the pigs blood? What were you hoping to do with that?

I tried to turn it into a fish sauce. It’s horrendous. It smells like death. We don’t do things in the lab with the hopes that it’s going to become something. We just do it to do it. And if the rest falls into place, great. If it doesn’t, you learn something.


Talk to me about how you started with this book, trying to distill all the fermentation knowledge down to something that could be handed to someone that knows nothing about it.

I started with the table of contents. I had never written a book before but it seemed like the best place to start.

I don’t know that that’s usually where people start.

It’s not?

I don’t think so.

How do you know what you’re writing about if you don’t know what to write about?

How do you know what goes in the table of contents if you haven’t written it yet?

You choose! You say, “I’m going to write about this and this and this.” But that was actually pretty easy, because we have seven rooms in the restaurant that are each a style of ferment. And within each of those rooms, you can find dozens of products so it was about going into each room and being like, “This will be a chapter, we will go from easiest to hardest, and I will pick the ferments that are both most representative of what we do at Noma and also the most approachable to people.”

I don’t mean this in a bad way, at all, but your book is such an esoteric cookbook. How do you envision people using this and why? Why would someone who doesn’t have a fermentation lab want to start fermenting?

Because it’s fun. It might be esoteric but it’s only esoteric until you do it, because then it’s a body of knowledge that’s known to you. Look, you can just walk into this kitchen: There’s a container, there’s salt, open a fridge, there’s something I can ferment. Everyone has all this stuff in their kitchens anyway. You probably have a container or a jar, a Ziploc bag, salt, and a fruit.


So should everyone ferment?

It’s a great way of democratizing food. I think fermentation is scary to some people because it’s been held behind the shuttered doors of long corporations for a very long time. People don’t know how beer is made, even though beer has only ever been made by people, which is a bit strange. The fact that beer became giant corporations, with Budweiser and whatever, it’s all well and good; that’s just capitalism doing it’s thing. But these are processes that were made by people. We haven’t invented anything new here; we’ve just looked at it upside down and said, “What if?” But the only reason we’re even able to look at these processes is because they’ve been kept alive, handed down as cultural artifacts as well as living artifacts for thousands of years. Not by corporations, but by people who just needed to keep themselves alive and feed themselves.

When you’re at home, you’re not at Noma—

I don’t ferment at all—I do that enough at work.

But what do you take home with you?

The garums. They’re like secret weapons. If you’re cooking anything savory, and even if you’re cooking something sweet, a splash of garum is like turbo juice for your food.

The book is at once highly technical and also the recipes are sort of loose guidelines. Is fermentation more of an art or a science?


That’s kind of a cop-out.

No, it’s not! I was asked this question this morning, actually, during a Q&A at a university. Someone was like, “You know you talk about hand taste, and the nuance of fermentation, and you can’t control it. Meanwhile, you work in a laboratory and use science to understand it, so where’s the breaking point? How much can hand taste control?” You can control things up to the point where you can’t. Like, you are not in control of the microbes. You can only set up conditions so well that they go as good as you can hope for them to go. You’re a shepherd, not a conductor. You’re coercing them into doing kind of what you want them to do. And you can use science to do that very, very precisely, up to a point. At which point life takes over. Like Jeff Goldblum in Jurassic Park, 1992, “Life finds a way.” And at some point you will have to submit your human desire to control the scenario and let nature take its course. And that is the most thrilling part of fermentation. It’s as much a science as it is an art.


So, are you done with the fermentation thing now?

Well it’s funny, you know, we’ve put it all out there. Let’s say, the products that we come up with that actually go to market—not that the others aren’t successes, restaurants all over the world would be happy to just step into Noma’s pantry like, “I’ll take this, this is amazing.” But for Noma, it’s gotta be like the crème de la crème. The test kitchen gets to skim like the best 5 percent of the shit we do. So sometimes it feels like I’m pushing this giant boulder up a hill and I’m never going to reach the top. You’re never done. You just have to look closer, find a different rock to overturn.

But at the same time, it’s also kind of liberating to put this out there and be like, OK, left turn. Now, I’m big into aromas and I have something called a supercritical fluid extractor in the lab, which allows me to make smells.

What are you going to do with smells?

Right now, the first course at Noma is a mushroom and forest broth. So it’s a mushroom tea that is poured through this bed of moss into a cup and you have to drink through the moss, seasoned with squirrel garum and then aromatized with the scent of the forest floor.

And how do you get the scent of the forest floor?

We send our foragers out. I tell them, “Go into a clearing and bring me back a kilo of the same shit you see in the same proportions. Go after it rains and get me moss, earth, bark, twigs, leaves.” They bring it back, I dehydrate it, I grind it up, I put it through my supercritical fluid extractor.

Do you miss actually cooking in the restaurant?

Yeah. But my world is big now. Bigger. And it’s growing. Cooking in a restaurant is a good way of being extremely focused, which can be liberating and thrilling—to be like, “This is my world and mine alone.” And I’ve been a cook my whole life; that’s something I love and crave, but there’s this other world. I’ve discovered sharing knowledge, which is a thrill. To know something about the world and to be able communicate that and see people enjoy it, and not just enjoy it but take a part of it, that’s a whole other level.

Thanks for speaking with us.