Americans used to find yogurt yucky. But the creamy dairy food long ago joined beer and cheese on the list of our favorite things produced by fermentation — an ancient preservation process in which bacteria transform food and drink, creating new flavors and, many consumers believe, enhanced health benefits.
So maybe it’s not surprising that thousands of people now show up at fermentation festivals around the country to make sauerkraut and sample kombucha teas, Korean kimchi and Japanese natto. The same folks flock to pop-up “kraut mobs” and study books such as Wild Fermentation and The Art of Fermentation, both by the movement’s guru, Sandor Katz.
“I would say that virtually every event I do these days is at capacity, and I’m not accepting every invitation. I can’t physically do it,” Katz says. He spoke from China, where he was on a quest for more fermentation wisdom.
Fermentation is the hottest trend in plant-based eating, according to recent survey of registered dietitians by The Monday Campaigns, a non-profit organization that promotes healthy lifestyles.
Jeremy Ogusky, a Boston pottery maker, sees it firsthand as founder of Boston Ferments, the host group for a summer festival that drew a few hundred people four years ago and 14,000 this year. “It’s just grown every year,” he says. “It’s kind of crazy.”
Among the foods causing the excitement:
Sauerkraut. The classic sandwich-topper — made from shredded or chopped cabbage, salted and jarred in its own liquid, then left to ferment for a few weeks before going into the refrigerator — is “the gateway drug” for do-it-yourself fermenters, Ogusky says. It’s familiar and easy, he says: “It’s just cabbage, salt and time.”
Kimchi. A traditional Korean side dish that often starts with cabbage and can include other vegetables and seasonings such as chili peppers.
Kombucha. A drink made by adding a starter culture of bacteria and yeast to tea, sugar and other flavorings. It can contain varying amounts of alcohol (commercial versions marketed as non-alcoholic are limited to a trace amount).
Natto. Fermented soybeans from Japan.
Miso. A Japanese seasoning, made from soybeans.
Flavor drives a lot of the interest. “The most compelling flavors in the world come from fermentation,” Katz says. There’s also a practical aspect: Fermentation preserves food — which is why it has been around for thousands of years and, Katz believes, in every culture.
But many fermentation fans also are in it for the bacteria, the stew of organisms produced along with all those tangy foods and drinks. Aficionados, with some backing from lab and animal studies, most often cite benefits to gut health and immunity.
That thinking is in line with science suggesting overly sanitized environments may mess up the microbes in our bodies, leaving us more vulnerable to allergies, infections and digestive complaints.
“We’ve had this war on bacteria for sixty years,” says Ogusky, who has a master’s degree in public health and has worked in that field. “Fermentation is the opposite of that. We are embracing bacteria.”
But calling the bacteria in most fermented food “probiotics” — meaning bacteria with known health benefits — is getting ahead of the science, says Wendy Dahl, an associate professor of food science and nutrition at the University of Florida. She says only a few strains of bacteria, found at sufficiently high doses in some yogurts and supplements, have gone through the human testing required to back health claims. Those studies have been funded by yogurt and supplement makers, she notes.
Some other fermented foods may come with beneficial bacteria, she says, “but they need to be tested, and research is expensive.”
Vegan cookbook author Jill Nussinow, a San Francisco-area registered dietitian, says she believes that “the gut benefits are real.” But she says, “the flipside of that is that people really need to pay attention with this stuff, because you can get too much,” and end up with bloating, diarrhea and other unpleasant effects.
She suggests newbies start with a “gut shot,” usually a straight shot of sauerkraut juice. It’s easier to digest than the fibrous whole food would be, she says.
And what about safety, especially for foods fermented at home? After all, the process typically requires leaving jars of foodstuffs sitting out for weeks, without the final sanitizing steps used in standard canning. (Heat processing can be added for some foods, but purists generally frown on that.)
The history of fermentation, especially with vegetables, is mostly reassuring. When properly done, fermentation produces acids that kill most worrisome microorganisms, says Benjamin Chapman, an associate professor and food safety extension specialist at North Carolina State University.
“We have lots of data showing that if you get the correct pH drop, the correct acidity level, you can create a really, really low risk product,” he says. But he says risks are not zero, and some cases of home fermenters making mistakes and creating unsafe foods have been reported. That’s why he urges people to use only long-tested recipes and techniques.
Information on home fermentation is at the website of the National Center for Home Food Preservation.
Kim Painter, Special for USA TODAY