If you’ve ever set out to make your own sauerkraut or kimchi but were worried about making somebody sick in the process, you’re not alone.

“There is a tremendous fear in our culture of aging food outside of refrigeration,” writes Sandor Ellix Katz in The Art of Fermentation (Chelsea Green). “Most people are raised to view bacteria as dangerous enemies and refrigeration as a household necessity. The idea of leaving food outside of refrigeration in order to encourage bacterial growth triggers fears of danger, disease, and even death.”

But fermenting cabbage—thereby transforming it into sauerkraut or kimchi, depending on the seasonings—is “pretty foolproof”, Katz emphasized to an audience during a recent visit to Vancouver. “If it was so intrinsically dangerous, we wouldn’t be here talking about it.”

The Tennessee-based author and self-taught “fermentation experimentalist” was in town for a series of workshops, including this one on February 1 at the Northwest Culinary Academy of Vancouver. His talk attracted experienced fermenters (many of whom brought copies of his 2003 bestseller Wild Fermentation for signing) and newbies alike. Katz’s message to both groups: “Don’t be afraid to experiment.”

A decade after his Wild Fermentation was released, Katz said he’s “still constantly learning things, making mistakes, learning things from my mistakes”. At almost 500 pages, The Art of Fermentation, which came out last year, is considerably more in-depth than his first book. It covers a wide range of edibles, including pickles, yogurt, sourdough starter, miso, tempeh, and cured foods like sausages and olives. It also covers fermented beverages such as kombucha, beer, and mead.

“None of this is rocket science,” he told participants. “Our ancestors with far less technical understanding than us have been doing this for thousands of years.” He noted that for most of human history there was no refrigeration, and there still isn’t any in many parts of the world. People have nonetheless found ways to preserve the harvest—or an abundance of meat or fish—often through fermentation.

So what is fermentation, exactly? Katz explained that the plants and animals we eat are covered in microorganisms. “Fermentation is the transformative actions of microorganisms,” he said. While a cabbage left on the counter for days will mould, refrigerating it slows down the process. But rather than refrigerating it, if you submerge it in liquid so that it has no access to oxygen, lactic-acid bacteria will grow instead. This helps to preserve the vegetable and at the same time makes it more digestible—not to mention nutrient-rich and delicious.

“Fermented foods live in this creative space between fresh and rotten,” he said, and their consumption is deeply rooted in many cultures. But they can also be something of an acquired taste. So while one person delights in stinky cheese, another deems it unfit to eat; one adores fish sauce, and another can’t stomach the thought.

While there are food-safety precautions to keep in mind, especially when working with meat or fish, Katz said that vegetables are a good starter ferment. In his book, he quotes Fred Breidt, a microbiologist with the U.S. Department of Agriculture. “Risky is not a word 

I would use to describe vegetable fermentation,” Breidt states. “It is one of the oldest and safest technologies we have.” (Anyone with lingering concerns may want to consult precautions on the National Center for Home Food Preservation website.)

The Art of Fermentation includes detailed instructions on how to make sauerkraut and kimchi, including choosing a suitable container, and chopping, bruising, salting, seasoning, and packing the cabbage. “The most important single factor is to submerge the vegetables under liquid,” Katz said as he demonstrated the process. That prevents mould from forming.

“The million-dollar question is, ‘How long do you ferment it for?’ ” he said. “There’s no answer.” Both personal taste and cultural preference dictate when your ferment is ready to eat. For sauerkraut, that could be three days, three weeks, or three months. Katz enjoys eating sauerkraut throughout the process but picks the six-week mark as his ideal.

When your sauerkraut reaches the state you desire—it gets stronger and less firm as it ages—move it to the fridge to slow the process. “One of the best things about making it yourself is you can make it the way you like it,” Katz said.

Eileen Muzzin, who has been an active fermenter for several years, agrees. At the workshop, she told the Straight she prefers the strong kimchi she makes herself—with lots of garlic—over commercially available products. It’s also a way to preserve the cabbages she grows herself.

Muzzin’s projects have included yogurt, crème fraîche, sauerkraut, turmeric-spiced pickles, and more. She also makes tempeh, a soybean ferment that requires a more complex, temperature-controlled process. “We’re hoping we can make it in a way to suit our taste more,” she said, so she and her fermenting partner are trying out different grains and legumes in place of soybeans.

Except for one “funky” batch of kimchi, Muzzin has had success with all her ferments. And, like Katz, she’s happy to keep on experimenting.