For years, Sandor Katz has been fermenting foods, convinced that the probiotics they contain are keeping him healthy despite his compromised immune system.

For years, Sandor Katz has been fermenting foods, convinced that the probiotics they contain are keeping him healthy despite his compromised immune system.

To hear Sandor Katz tell it, our world would be a very different place without fermented food. It's not merely that we wouldn't have much of the fare we cherish most: wine, beer, cheese, yogurt, to name but a few.

Indeed, says Katz, without fermentation and the preservative qualities it imparts, we'd never have built cities, or cars, or iPads, because we'd never have evolved from our hunter-gatherer status. "We could not have developed agricultural societies without the fermenting techniques that allowed us to store food," says Katz, a tall man of 47, with an unruly mop of hair and thick muttonchops that connect to an equally vigorous mustache.

Fermentation is a process whereby carbohydrates in a food or beverage break down to form alcohol-in the case of wine and beer-or lactic acid, which preserves foods. (In the latter scenario, also called lacto-fermentation, "good" bacteria, or probiotics, drive the transformation.)

These days our homes are graced with freezers and refrigerators (Katz calls the latter "fermentation-slowing machines"), but these devices haven't halted an interest in the craft of fermentation, which has helped Katz sell more than 50,000 copies of his book Wild Fermentation, published by Chelsea Green in 2003.

Some of this attention to fermentation is no doubt owed to the growing interest in homegrown foods and the subsequent issues of preserving harvests through the winter; for instance, sauerkraut, made from cabbage, is one of the better-known fermented foods. Some of the interest might be credited to economic woes, as people may see fermenting the harvest as a way to cut their food bills. But part, surely, must be ascribed to Katz himself, who has become something of a food celebrity, crisscrossing North America on a mission to connect the dots between fermented foods, good health and cultural evolution.

Rise of a Fermentation Fetishist

There was nothing in Sandor Katz's background-besides a fondness for sour pickles-that suggested he'd become a self-proclaimed "fermentation fetishist." He was born in New York City, where he lived until 1993, when he moved to rural Tennessee to become part of an intentional farming community for gay men known as Short Mountain Sanctuary. Katz had recently been diagnosed with HIV, and after years of urban living, was looking for something different. "I was ready for a big change," he recalls. "I'd begun exploring herbalism and wanted deeper relationships with plants and was desiring healthy living after testing HIV-positive." At Short Mountain, he planted his first garden and, in his words, "faced the classic decision all vegetable gardeners have-what to do with all the radishes that are ready at the same time."

That led him to the technique of lacto-fermenting, a centuries-old method of food preservation that involves submerging chopped-up raw vegetables in brine to create an environment that encourages the growth of healthy bacteria, including strains of the same probiotics found in yogurt. (These healthy bacteria are often referred to as "live, active cultures.")

"People think of fermentation as something mysterious, but all you're doing is manipulating the environmental conditions to encourage the growth of some beneficial microorganisms and not others," explains Katz. "When prepared properly, fermented vegetables can be stored unrefrigerated and uncooked for months." That's in part because well-prepared fermented vegetables are submerged in brine, making them more impervious to invading bacteria that would cause them to rot or spoil.

What's more, says Katz, fermented raw vegetables (as well as other cultured foods, such as yogurt and kefir, or fermented milk) offer unique health benefits by infusing the gut with healthy bacteria and also by increasing the bioavailability of minerals and vitamins. "As fermentation progresses, it creates lactic acid," explains Mingruo Guo, Ph.D., a professor in the University of Vermont's Department of Nutrition and Food Sciences. "This makes minerals more soluble.

It also produces enzymes that help break down proteins and fatty acids, which can help digestion."

Clinical evidence supporting the health benefits of probiotics-particularly in supplement form-is mounting. For example, a study published in the journal Pediatrics last spring showed that taking probiotic supplements can reduce fever incidence due to colds and flu in children by nearly 73 percent. That's all well and good, but as Katz says, "Why would you pay a lot of money to get your nutrients in a [supplement], when you can get them in your food for next to nothing?"

But are fermented vegetables (uncooked, unrefrigerated) safe? "I truly believe that fermented vegetables are safer than raw," says Katz, who ferments his kimchi in a 55-gallon wooden barrel that once contained Jack Daniels. "You're creating a competitive situation that protects you from pathogens, so even if you ended up fermenting a cabbage leaf that had E. coli on it, the good bacteria would overwhelm the bad and you'd never get sick." A bit of an oversimplification, says food-safety expert Douglas L. Archer, Ph.D., associate dean for research at the Institute of Food and Agricultural Sciences at the University of Florida in Gainesville. "E. coli 0157:H7, as well as the Salmonella family of bacteria, are quite stable in acidic environments," says Archer. "While fermenting may lessen the chance of illness, it is not foolproof."

Guo explains how fermentation can make foods a little safer: "When you ferment foods, they become more acidic, which inhibits the growth of potentially harmful bacteria. At the same time, they are producing antimicrobial compounds [that help to thwart bad bacteria]." Guo grew up in China, where lacto-fermenting is still a common food-preservation technique.

Most folks probably don't ferment vegetables because it makes their food safer. But a growing number of people are turning to probiotic-rich foods for their associations with improved health; no doubt some of these enthusiasts have been encouraged by Katz's testimonial in Wild Fermentation: "[N]othing is a panacea, and fermented foods did not prevent me from developing AIDS," he writes. "I've lived through harrowing downward spirals.... I take anti-retroviral drugs, but many different factors, including regular consumption of live fermented foods, contribute to my present robust and energetic state.... Tangible health benefits have only encouraged my devotion to fermentation."

Contributing editor Ben Hewitt is the author of The Town That Food Saved (Rodale Books, March 2010).

Contributing editor Joyce Hendley is an award-winning science journalist who specializes in writing about food and nutrition.

November/December 2010