René Redzepi has a simple message for cooks: Think microbes.

And not just any old microbes — there are, of course, good ones and bad. He is focused on the ones that give us kombucha, miso and vinegar — as well as cheese, kimchi and pickles, and so much more — which make such a difference on the dinner plate.

Redzepi’s words may bear more weight than most as chef and co-founder of Noma in Denmark, the restaurant that has four times been named No. 1 in the world. He has been credited with inspiring a new Nordic cuisine.

Redzepi will be in the Twin Cities on Friday at the American Swedish Institute as part of its Nordic Table Chef Series, with David Zilber, his fermenter-in-chief and co-author of “The Noma Guide to Fermentation” (Artisan, 456 pages, $40). The comprehensive volume, with step-by-step photos, will likely land on many holiday wish lists. (Tickets for the event are sold out.)

Redzepi chatted by phone about the ability of home cooks to MacGyver a fermentation chamber out of a Styrofoam cooler (think electric blanket, screws and a temperature controller), the importance of cleanliness in the fermentation process, and his favorite forager.

Q: You say the defining feature of Noma is the fermentation. That may be a surprise for cooks who think of you and the restaurant as focused on foraging.

A: When we talked about this aspect in the kitchen at Noma and started to define what makes us who we are, we said it was first the people and the character of place. What started everything is the landscape stepping in. What made a difference is fermentation. It was a way to create building blocks that we can cook with. It made our food what it is today. There’s not necessarily a wild forest ingredient on the menu everyday now, but there is always something fermented on the menu all year.


Q: Home cooks want reassurance on the safety of these procedures. What advice can you give?

A: Our general advice is to follow the instructions as we have described them. It is true, you need to take care and know what you’re doing. Learning how to do this requires a little bit of research beyond what people have normally.

That’s very important. Once that happens, it’s like knowing when a fish is fresh or not. It’s like how you know when an apple is good or not. If it’s wrong, it’s so wrong you are not in doubt with it. And there is always the option of heating to a proper temperature if people are very worried about that. The book offers clear instructions to provide a safe and delicious product. If you follow it closely, it becomes a part of you. And you shouldn’t eyeball measurements and take shortcuts. Cleanliness is critical. Be clean, and then you are on the way.


Q: How did you learn the chemistry involved in these procedures?

A: We hired a Ph.D. in chemistry, who was with us for almost two years. David Zilber and others [at the restaurant] all have that knowledge. I wish I could say I was as knowledgeable as they are, but I’m more like an average cook; maybe I understand a tiny bit more. We are so cautious of that. We wanted the instructions to be not too technical, but wanted to teach some things. We didn’t want to look like we were taking all the knowledge off of a Wikipedia page.


Q: I love the sense of building your own lab for home cooks from the hardware or restaurant supply store. Can you explain?

A: You can go quite far with good old grandma’s heating blanket and a Styrofoam box. It’s very practical. That’s how we started out when we first built these things. We were trying to emulate tropical environments. At home, you don’t need a big setup like we have now.


Q: I was surprised to see the name of Euell Gibbons, the popular forager of the 1960s (“Stalking the Wild Asparagus”), pop up in your book. What is your connection with him?

A: Many years ago, in the opening years of Noma, I came across Euell Gibbons as I was frantically looking for information and for someone to inspire and guide us. Noma opened 15 years ago, and it was very difficult. I was 25 and wanting to do this work and had no one to talk to about it. I came across a book by Euell Gibbons, maybe in San Francisco’s Omnivore Bookstore. He had a refreshing way of writing about a subject and explaining how to cook. We were quite inspired by his book in general.


Q: Cooks think of fermented items as only an item to use itself. But you go so far beyond that with how to use the leftovers. This is truly a no-waste approach to food.

A: The common home cook who knows only a little about fermented foods knows about sour cabbage, which is hardy and funky and made for winter. But the reality is that those are only the tiny drops in a vast ocean of ideas. The process of making kraut is lactic acid fermentation. Everything can be made into kraut. We have done this with so many ingredients, including making kraut out of gooseberries. There’s a lot more to be found and innovated on. The only problem is us not seeing that opportunities are everywhere. The world of microbes is endless. Imagine a single grain of rice and think of all the food stuffs, drinks or alcoholic beverages that can be made from it. All those have come from imagination and accidents. Not everything has the potential of rice grain, but even a 10th of that is astonishing. We are waiting to unlock fresh opportunity. All the fermented amazingness out there will make others cook more and experiment more.


Q: Have you been to Minnesota before?

A: As a Scandinavian, it’s always a place we hear of, a place I’ve never been but feel there’s a connection to, from all the stories of Scandinavians that went there. Most Scandinavians feel quite close to it.