Ingredients, temperature, time all have an effect on the microbial exercise that fuels fermentation — and the way fermented meals style. As kimchi ferments, the flavors will change over time.

Meredith Rizzo for NPR

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Meredith Rizzo for NPR

Ingredients, temperature, time all have an effect on the microbial exercise that fuels fermentation — and the way fermented meals style. As kimchi ferments, the flavors will change over time.

Meredith Rizzo for NPR

I really like fermented meals. I really like that you may go away one thing out on the counter, within the fridge — neglect about it, even — and it simply will get higher.

But why do some meals enhance with age, whereas others spoil? I wished to know the way it occurs.

So early one morning, I met Chef Patrice Cunningham at Tastemakers, a shared business kitchen in northeast Washington, D.C. She owns a small enterprise, making and promoting a deliciously recent, spicy, fermented Korean condiment – kimchi.

Cunningham welcomes me with a handshake and a hairnet, and leads me to a big, metal prep desk coated with a few dozen crates of Napa cabbage. She and her three assistant cooks chopped every leafy head down into bite-sized items. It’s step one in reworking the uncooked and humble cabbage into bright-red, funky kimchi.

“I’m turning cabbage into gold,” Cunningham says, “We’re in here, busting our butts every day to provide good food to folks.”

Over the course of two days, Cunningham will stroll me by the steps of creating kimchi – and assist me perceive how an age-old meals processing approach allows the microbial magic of fermentation.

Cunningham types by packaged kimchi within the fridge.

Meredith Rizzo for NPR

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Meredith Rizzo for NPR

Cunningham types by packaged kimchi within the fridge.

Meredith Rizzo for NPR

As a toddler, Cunningham made kimchi along with her mom. But she hadn’t deliberate to make a residing from it, till the pandemic occurred — and she or he misplaced her job as a chef at a restaurant.

She puzzled what to do subsequent — after which an previous concept got here again to her. “I remember eating my mom’s kimchi and being like ‘This kimchi is the best!'” she recollects. “And I was like, ‘I should jar this one day.'”

So, three years in the past, Cunningham began her firm, Tae-Gu Kimchi, named after town in South Korea the place her mom is from. Her mom says this recipe is typical of Taegu – heavy on garlic, inexperienced onions and spicy pink pepper paste, packing sturdy flavors in each chew.

Cunningham and her workforce make the kimchi recent each week to promote at native farmer’s markets, however she has plans to broaden to e-commerce and wholesale, and hopes to promote nationwide sometime. “We’ll cross that bridge later,” she says, as she strikes on to the subsequent step in kimchi making: “Right now, I’m salting.”

Patrice Cunningham pours brine into tubs of chopped cabbage. The salty answer helps the pure fermentation course of by drawing water out of the cabbage leaves. As it sits, the leaves shrink and settle, releasing extra meals for the microbes.

Meredith Rizzo for NPR

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Meredith Rizzo for NPR

Patrice Cunningham pours brine into tubs of chopped cabbage. The salty answer helps the pure fermentation course of by drawing water out of the cabbage leaves. As it sits, the leaves shrink and settle, releasing extra meals for the microbes.

Meredith Rizzo for NPR

Salt, time, microbes

Cabbage leaves, like many different residing issues, are naturally coated in tiny yeasts and micro organism. These microbes are largely innocent whereas the cabbage resides, “but as soon as we take the cabbage out of the ground – as soon as the cabbage can’t defend itself – those [microbes] start using it as a nutrient source,” says Justin Sonnenburg, a microbiologist and immunologist at Stanford University.

When the cabbage will get harvested and chopped, these microbes begin consuming it – i.e., fermenting it.

In the kitchen, Cunningham helps the method by soaking the cabbage in a salty brine. She dissolves eight cups of coarse salt in a vat of water. “My mom did the measurements for me, so there’s no method to this madness other than this being her recipe,” she says. She pours the liquid over tubs of crisp, chopped cabbage.

Her mother — Hong Cunningham — typically stops by the kitchen to assist with the method and see that she’s following the household recipe proper. “It’s almost the same,” Hong says. “Almost the same,” Patrice echoes, laughing.

Patrice Cunningham (left) began Tae-gu Kimchi in 2020, basing her recipe from her mom Hong Cunningham. Her mother nonetheless helps out and weighs in because the kimchi will get made.

Meredith Rizzo for NPR

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Meredith Rizzo for NPR

Patrice Cunningham (left) began Tae-gu Kimchi in 2020, basing her recipe from her mom Hong Cunningham. Her mother nonetheless helps out and weighs in because the kimchi will get made.

Meredith Rizzo for NPR

In 4 hours, the cabbage will take up simply half the bathtub. “It just all kind of shrinks,” Patrice Cunningham says. As the cabbage soaks, the salt attracts water out of the cabbage leaves. It breaks down cell partitions, releasing sugars that feed the kimchi-making microbes.

Those microbes break advanced sugars and starches aside with nice precision, explains Victor Ujor, a meals sciences professor on the University of Wisconsin Madison. “They take a starch that contains something like 15,000 molecules of sugar — and they go snip-snip- snip-snip-snip, into individual sugars. Then they take the glucose — boom! break it down,” he says.

The microbes flip the cabbage into vitality they’ll use and compounds that may sign one another, which additionally modifications the way it tastes to people. The outcomes? “This wacky, beautiful jumble of flavor and beauty,” Ujor says.

The key to a fermentation is getting the best microbes to point out up on the proper time. “It comes down to our ability to use salt or other factors to herd these microbial populations,” says Elisa Caffrey, a graduate pupil finding out fermentation in Sonnenburg’s lab at Stanford.

Salt offers the microbes key to kimchi-making a leg up, serving to them develop and outcompete different microbes that would rot the cabbage into one thing inedible. “The difference between [spoiling] and fermenting is that you’re selecting for certain microbes to grow that are beneficial to the end product,” she says.

Temperature, oxygen and competitors

To get the best ferment, you want the best situations. It’s early the subsequent day, and Chef Cunningham is again within the kitchen. She’s washed and dried the cabbage, minced a lot of garlic and combined up a spicy pink pepper paste. But there’s an issue – “It’s so hot in here,” Cunningham says.

It’s most likely round 85 levels. If it will get a lot hotter, dangerous micro organism may begin to develop.

Cunningham and her workforce work quick. They placed on pink rubber gloves as much as their elbows, add fish sauce and salted shrimp, and therapeutic massage a gooey paste made with spicy pink peppers and candy rice flour into the cabbage. The sound stirs up childhood kimchi recollections.

“On a hot summer day, my mom would be in the backyard. And you can just hear the squeakiness of rubbing the ingredients on the clean cabbage. Every time I hear it, it brings me back,” Cunningham says.

Once the kimchi is combined, the employees works to get it bagged and sealed, to maintain out oxygen – one other enemy of an excellent ferment. Low oxygen and growing acidity assist lactic acid micro organism thrive, together with Weissella koreensis, Lactobacillus sakei, and Leuconostoc gelidum which are key to making kimchi.

“It’s a competitive environment that eventually favors what we want,” Ujor says.

The ferment tends to be most energetic within the first couple of days, however then continues for a very long time, with successive communities of microbes. “One group will take over from another, and the work they do at different times is responsible for the texture, profile and flavor of the product,” he says.

Microbes and your intestine well being

Fermentation might help meals keep scrumptious and secure for a very long time, which is likely one of the major causes individuals began doing it within the first place. And a small however rising assortment of analysis reveals that consuming fermented meals might be good in your intestine, and would possibly assist enhance the immune system and keep at bay illness.

A couple of years in the past, Sonnenburg’s lab recruited wholesome volunteers to eat much more stay fermented meals than traditional – a mean of six servings a day of meals like kombucha, kefir, yogurt, kimchi, sauerkraut – and tracked variations of their stool. “As they increased fermented foods in their diet, their gut microbiome diversity increased, which we tend to think of as a generally healthy outcome,” says Sonnenburg.

The variety wasn’t simply coming from the microbes they have been consuming – these made up about 5% of the brand new biodiversity of their intestine, Sonnenburg says. The overwhelming majority of the newly detected microbe species got here from elsewhere – probably from the surroundings, or maybe they have been already there within the intestine at undetectable ranges till they have been inspired to develop.

The researchers additionally examined the volunteers’ blood, and located indicators that the high-fermented-food eating regimen considerably diminished irritation. These modifications weren’t present in a comparability group of volunteers who ate a high-fiber eating regimen, which is also associated with improved gut health.

Sonnenburg thinks it is attainable that consuming fermented meals could scale back the danger of ailments related to persistent irritation, comparable to diabetes, coronary heart illness, Alzheimer’s, and a few cancers. It’s a speculation he is working to check, he says, although the work has been transferring slowly as a result of restricted funding.

Some analysis suggests there could possibly be unfavorable impacts from consuming sure sorts of fermented meals. The World Health Organization lists conventional Asian pickled greens as a possible carcinogen – together with consuming very popular drinks and consuming processed meats – primarily based on restricted proof. Caffrey, from Sonnenburg’s lab, says the research linking fermented meals with most cancers are inconclusive.

“We need better studies that distinguish between fermented food types and quality,” to know what most cancers dangers would possibly exist, Caffrey wrote in an e mail. Still, she provides, if one thing smells or tastes off to you, or appears to be like prefer it’s rising mildew, do not eat it: “When in doubt, throw it out.”

Thanks, microbes!

There’s an infinite quantity of scrumptious variations that come from combining elements, temperature and time – and people hardworking microbes, says Ujor: “They don’t talk back at you, they don’t yell, they do all that work. They even die doing it, and they even release more flavors after they die. I think they are such beautiful things.”

You know, I’ve by no means appreciated microbes that method. Their work by no means seems in recipes and cookbooks. I hadn’t thought of how these tiny beings, invisible to the attention, flip milk into yogurt, soybeans to soy sauce, grape juice to wine. But I’ve loved their outcomes many instances, within the fizzy tartness of kombucha and the daring, complex tastes of chocolate.

And now, I wish to put savory, umami-rich kimchi on all the things – pizza, pasta, scrambled eggs.

The packaged kimchi will proceed to ferment within the weeks after it’s made.

Meredith Rizzo for NPR

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Meredith Rizzo for NPR

Back within the kitchen, Cunningham presents me a pattern of kimchi from the newly combined batch. It’s recent and scrumptious – crunchy, spicy, balanced with an excellent kick to it. The workforce hundreds packed baggage into the fridge, to maintain them recent for the market.

Hong Cunningham is clearly pleased with her daughter Patrice. “She does pretty good,” says Hong, “I just help a little bit now,” coming by to cut garlic and help with the packing. And she’s pleased with kimchi.

“For a long time, [most people in the U.S.] didn’t know what kimchi was,” she says. Now, like KPop and Korean dramas, she says the cabbage dish is bringing international fame to her tradition. And her recipe is reworking her household’s fortunes within the course of.

Photography by Meredith Rizzo. Editing and visible design by Carmel Wroth. Rebecca Davis edited the audio model of this piece.