It's Alive! Kraut Talk with Kathryn Lukas

Brie Mazurek, CUESA Staff
November 14, 2014

In a forkful of raw, lactofermented sauerkraut, there are billions of living microbes that support our health in ways scientists are only beginning to understand. While most store-bought kraut is typically pasteurized, killing off these tiny probiotic critters, kraut makers like Kathryn Lukas of Farmhouse Culture are going back to  traditional methods of making kraut that preserve the vibrant microcosm of friendly bacteria found in live fermented foods.

In anticipation of CUESA’s “Gut Feelings: A Discussion about the Microbes You Can’t Live Without” event next Wednesday, we talked with Kathryn about the weird and wild world of fermentation.

CUESA: What goes on inside the crock when you’re making a batch of sauerkraut?
Kathryn Lukas: When cabbage comes in from the field, it brings with it an entire ecosystem of organisms—bacteria, fungi, yeast, molds. When you add salt to the cabbage, you select for a specific type bacteria called lactic acid bacteria. The other organisms tend to not like salt, so they start to die off. As the lactic acid bacteria eat the sugar in the cabbage, they produce lactic acid and off-gas carbon dioxide. During that process, the cabbage continues to get more acidic and flavorful and eventually reaches a state of equilibrium. That’s how you know you have sauerkraut.

CUESA: How do you know you’re cultivating beneficial bacteria in that process?
KL: The lactic acid fermentation process is considered a heterofermentation process in the beginning, because there are a lot of different bacteria that are present and active. By the end of the process, it’s a homofermentation process because one particular type of bacteria, Lactobacillus plantarum, has dominated the scene. It’s so acidic that nothing else can live in it.

According to the USDA, there’s never been a case of food poisoning with properly fermented sauerkraut, so it’s kind of ironic that most commercially produced sauerkraut is now pasteurized. The only reason to pasteurize sauerkraut is if you want to move it around an industrial system, because kraut is easier to handle when it’s shelf-stable than when it has to be refrigerated.

CUESA: What are some of the benefits of live, unpasteurized sauerkraut?
KL: In terms of nutrition, I’m fascinated by the fact that vitamin B12, which is not present in cabbage in any way that we can capture and digest, becomes an important nutrient in sauerkraut. I also think it’s fascinating that we’ve evolved with the microbes in fermented foods. When I tried raw sauerkraut for the first time in Germany, it was delicious, but it was more than that. I felt this recognition that I had found an ally. My body immediately loved it. We’ve witnessed that experience with our customers. People have a shot of kraut juice or sample kraut for the first time, when all they’ve ever known was pasteurized kraut, and there’s a sort of awakening.

Because we coevolved with these bacteria and they have disappeared from our diet and our guts, I think there has been a large penalty from a nutritional and health perspective. Research on the human microbiome is going to shed a lot light on diseases that have developed in the last century as a result of losing some of these important microbes from our diets.

CUESA: What excites you about fermentation?
KL: I make kraut because it tastes great, and I’m really interested in the traditional aspects. Fermentation is a lost art, and it’s now a new paintbrush in our toolkit. We have opportunities to cultivate new types of microbes and flavor profiles when we put vegetables together that have maybe never hung out together before in a crock.

One thing I’m especially interested in is terroir. For example, there’s actually a sourdough bacteria named after San Francisco. It’s not possible to make the same sourdough in Kansas City as it is in San Francisco. The microbes don’t gather the same way. I taste people’s kraut from around the country. I know they’re doing the same thing I’m doing, and I know they’re good kraut makers, but their kraut tastes different from ours. I think we’re developing a distinctive farmhouse flavor as a result of our location.

Because we’ve got great weather, California is the perfect place for a host of organisms that like to play nicely together. They say 64 degrees is the ideal fermentation temperature for lactic acid fermentation. I’m able to regulate my fermentarium by turning light bulbs on and off throughout the year. I think being by the ocean also does something interesting for the microbes, maybe it’s the salt water in the air.

CUESA: Have you ever had your kraut tested to see what’s living in it?
KL: We have, and it’s complex. There are all kinds of bacteria that are in our kraut that are really good, not just Lactobacillus plantarum, but we don’t know if they’re probiotic. We just know that they all tend to hang out together. When you isolate just one of these organisms and put them in a pill, it’s a little reductionist. There’s too much going on to understand how the bacteria interact.

We’re also finding that there’s some die-off of probiotic bacteria when we test our krauts that are quite a bit older. There’s still probiotic bacteria, but nothing compared to the billions, and in some cases trillions, in the really fresh stuff. I think California will probably become the epicenter of lactic acid fermentation because it’s the only state in the country where we can get cabbage year round and make kraut every single day of the year.

The research on the microbiome is opening up the world to us in ways that it’s hard to fathom. It’s like we just figured out the world is round, but we don’t know what it means yet.

Try Farmhouse Culture sauerkraut at the Ferry Plaza Farmers Market on Saturdays. Learn more about beneficial bacteria at “Gut Feelings: A Discussion about the Microbes You Can’t Live Without” next Wednesday, November 19, at the Ferry Building. RSVP.

Photos courtesy of Farmhouse Culture.

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