Kimchi 101: It Ain't Just Cabbage

Deuki Hong still remembers the day he discovered what kimchi really was.

As is true for most Koreans, "There was never a time in my life when kimchi wasn't in my refrigerator," says Hong, the renowned chef and coauthor of the cookbook Koreatown. But when he started learning to cook in middle school, he was always more interested in watching Jacques Pépin reruns on the weekend than in the fiery red fermented cabbage that was always in the kitchen, which, to him, symbolized his inherited knowledge of everything about Korean cuisine.

Then his mother took him to the grocery store in New York where she'd been buying their kimchi.

"There was this whole section of red and green and white," he says—jars of heart-shaped perilla leaves and soybeans, and, traumatically, little quart containers of shucked oysters and julienned carrots. All of it looked both familiar and totally foreign.

"I was like, 'What the hell is that?'"

Kimchi, she shrugged—all of it.

"It was a culture shock to me, even though it was my own culture," Hong remembers. "I thought [kimchi] was just one dish."

Hong's experience ended happily—it prompted him to explore Korean cuisine more deeply, even as he worked his way up through fine-dining kitchens to become the executive chef at the celebrated Kang Ho Do Baekjeong in New York, a position he has since left. But his initial confusion is also emblematic of a larger trend, spurred by Korean cuisine's growing popularity around the world. As kimchi pops up in increasingly unlikely culinary contexts—pizza, tacos, even doughnuts—the misconception that it is a single pungent side dish has taken hold.

That pungent dish is baechu kimchi, the variety made from Napa cabbage and typically seasoned with the slightly smoky, coarsely ground red pepper known as gochugaru, plus garlic, ginger, and some kind of fermented or fresh seafood. It's tangy, often spicy, and, appropriately, it gets the most attention: Baechu kimchi can be found in nearly every Korean home or restaurant, and much of the 57 pounds of kimchi reportedly consumed by the average Korean per year is of this variety.

But kimchi is a lot more than cabbage. The term "is actually more of an active verb," says Lauryn Chun, the founder of Mother-in-Law's Kimchi and the author of an excellent primer on the subject, The Kimchi Cookbook. "You can 'kimchi' just about anything."

How Kimchi Is Made

The word kimchi is derived from the Chinese characters for "salted vegetables," but the process Chun refers to actually involves four stages: brining, seasoning, fermenting, and storing. Brining creates an environment inhospitable to harmful microorganisms, while encouraging the growth of good lactobacillus bacteria. Those friendly bacteria eventually convert the natural sugars in the vegetables into lactic acid, a preservative that is also responsible for kimchi's distinctive tang. The salt in the brine also "opens the pores" of the vegetables to absorb the seasoning, Chun says, which is applied after the brining step either by smearing the vegetables with a seasoning paste or submerging them in a highly seasoned solution. The kimchi is then left to ferment in airtight containers, to mitigate the risk of contamination by airborne microorganisms.

"It's like aging wine," Chun adds. "You don't want to open it until you're ready to drink it."

While the fermentation process is often begun at room temperature, it's typically continued in a colder environment, which helps the kimchi keep for longer. Traditionally, this was accomplished by placing the kimchi in storage pots, called onggi, either underground or in the shade. These days, kimchi is packed in glass or plastic containers and stored in refrigerators—particularly the kimchi-specific models that rank among the most coveted appliances for Korean households.*

*As kimchi ferments, its lactic acid content increases, though the speed of fermentation is dependent on temperature—higher temperatures will make the kimchi ferment faster. Traditional refrigerators rely on air circulation, which means the temperature within the appliance can vary substantially. It's not enough to make other raw foods dangerous, but it can affect the acidity in kimchi, and thus its shelf life. Kimchi refrigerators, in contrast, are designed to maintain steady temperatures by cooling the inner walls of the appliance, which mimics the consistent temperatures achieved by burying onggi underground. The dedicated refrigerator also offers the benefit of keeping strong aromas from seeping into everything else you'd otherwise be storing nearby.

The basic process is highly variable, and there are literally hundreds of foundational recipes, as well as innumerable regional or even family-specific variations. Kimchi is made from all kinds of vegetables, including esoteric ones like burdock root and sweet potato vines, which means it also comes in a rainbow of colors. It can arrive swimming in a broth, or plated as dense hunks coated in seasoning. It can be fermented anywhere from a few minutes to more than a year, and, as Hong learned, it doesn't even have to be made entirely with vegetables—ingredients like oysters, anchovies, salted shrimp, and squid are sometimes included.

Kimchi in Korean Culture

Whatever it's made from, kimchi is hugely significant to Korea. Hyungsoo Yim, a chef at the Institute of Traditional Korean Food, explained to the BBC that kimchi isn't "just food—it's a kind of Korean soul." As a result, millions of dollars have been spent over the years to ensure that Koreans never have to go without, no matter how dangerous or distant their location. During the Vietnam War, the United States financed the production of battlefield kimchi to boost the morale of Korean soldiers, who were reportedly miserable without it.** Nine years ago, the Korean government spent millions producing so-called "space kimchi" that could accompany the country's first astronaut into the universe.

** In what seems like a testament to both the dish's importance and the state of his own marriage, Chung Il Kwon, the country's prime minister during the war, told then president Lyndon Johnson that when he traveled, he "longed for kimchi even more than he [longed] for his wife back in Korea," according to declassified notes on the meeting.

Kimchi's origins, however, are rooted in pragmatism. Its earliest form was developed in China sometime around 50 BC, but it was soon adopted on the Korean Peninsula as a necessary preservation technique in a region with little arable land and brutal winters. Within a few centuries, even the Chinese were remarking on the region's prowess in producing fermented foods. (It is important to note, though, that what was being made at the time bore little resemblance to the many varieties popular today—red pepper wasn't introduced to the peninsula until the 16th century, and Napa cabbage didn't arrive until several hundred years later.)

Even though most vegetables are now available year-round in Korea, the way kimchi is produced and eaten is still closely linked to the seasons. According to Chun, kimchi can be broadly categorized by the time of year when it is made—it's "a celebration of the vegetables in season, from the first-of-the-season scallions to whatever's being unearthed or growing in the fields, to cucumbers or radishes and the radish tops." Varieties for the fall and winter are typically made using root vegetables and fermented longer, to pad out the larder for historically frigid, foodless winters. Spring and summer kimchis are lighter and more delicate, and may be fermented for only a few hours, reflecting the relative abundance of the warmer months.

While the true diversity of kimchi can be experienced only by booking a flight to Seoul, here are a few of the most common varieties, likely available in your local Korean restaurant or supermarket. With a little time and effort, all are easily replicable at home, too.

Baechu Kimchi (Cabbage Kimchi)

Although baechu kimchi is a relative newcomer to the category, its popularity and ubiquity stem in part from its season. Cabbage is a fall and winter vegetable, and among the last to be harvested before the ground freezes over. For that reason, it "becomes most precious because you have to preserve it through the winter months," Chun says, "until you have the first seasonal vegetables again in the springtime with the scallions coming up from the ground."

Historically, that necessitated producing huge quantities during late autumn, which became a collective ritual known as kimjang. Kimjang continues to this day, further cementing baechu kimchi's significance as a means of bringing people together. Every year, entire communities gather to help each other make enough baechu kimchi to last the winter. Growing up in Seoul during the 1970s, Chun remembers her neighborhood producing upwards of 300 pounds each year over the course of three days—one day dedicated to brining; another to stuffing the cabbage with the seasoning paste, called sok; and the last spent storing the cabbage in pots to ferment. "It was like a kimchi block party," she says, laughing.

"Many families often eat boiled pork belly on the days we make kimchi," adds Junghyun Park, the chef behind Atoboy in Manhattan. "The pork flavors go so well with fresh, unripened baechu kimchi pre-fermentation," called geotjeori.

Like all kimchi, baechu kimchi is served as one of the many side dishes, known collectively as banchan, that accompany most meals in small quantities and are expected to be limitlessly refilled. But it's also used as a central ingredient in many popular dishes, like kimchi jjigae (kimchi stew) or kimchi bokkeum (kimchi fried rice).

While the ubiquity of baechu kimchi means its ideal form is hotly contested—when everyone's mother makes a different version, it's difficult to agree—Hong says a good baechu kimchi has balanced flavors at the outset, which are then allowed to develop over time.

"Good baechu kimchi definitely has that seasoned cabbage, that spiciness from the red chile, that umami from the fish sauce or the salted shrimp—and then it has that little bit of sweetness from the fermentation," he says, adding that, ideally, it'll ferment for a few weeks. With fresh baechu kimchi, the individual flavors of the ingredients will be sharper and more distinctive. But as the kimchi continues to ferment, they'll meld, and the overall flavor profile will change, becoming increasingly tangy as its spiciness develops into a deeper, earthier funk with a bit of sweetness, as well as a slight carbonation on the palate.

"With time, it develops these flavors that you can't really mimic with sugar or adding a little more salt," Hong says. "I like that you can't cheat kimchi."

According to Chun, most store-bought kimchi is already between a few weeks and a month old, though it'll keep much longer than that. Kimchi doesn't really go bad as long as it's not exposed to air, which can contribute to mold growth, but it does get increasingly sour as time goes on. If it's too sour to eat raw, it can still be cooked into other dishes.

Baek Kimchi (White Kimchi)

Baek kimchi (literally "white kimchi") refers broadly to all kimchi made without gochugaru. Though it's often produced using Napa cabbage, it can include just about any vegetable. That can mean sweeter ingredients are incorporated, like pear or jujube, but the lack of spiciness also allows the base ingredients to shine. "There's clarity in the flavor of the vegetable that comes through the fermentation," Chun says. "[Baek kimchi] should be something that tastes really bright, and it should be crunchy."

Another characteristic prized by both Chun and Park is the "spritziness" or "fizziness" from the fermentation, which is more apparent in baek kimchi than in other, funkier varieties. When it's paired with additional sugar from the fruit, Park compares good baek kimchi to Sprite, with its balance of sweetness and acidity.***

*** David Chang, of Momofuku fame, actually uses 7-Up soda in one baek kimchi recipe, to increase the fizz and the sweetness.

Those features make baek kimchi a refreshing accompaniment to dishes with more heat. According to Hong, "You'll eat a really spicy stew, where it's chile-based or gochujang-based"—like yukgaejang (spicy beef soup with vegetables) or dakdoritang (spicy chicken stew)—"and you'll eat baek kimchi instead of [drinking] water." But, like all kimchi, the variety isn't really beholden to a particular meal or occasion. "On a hot summer day, I could just eat baek kimchi and be happy," Hong says.

Kkakdugi (Cubed Radish Kimchi)

Another common variety is kkakdugi, or cubed radish kimchi, usually made with a Korean variety of the vegetable known as Joseon radish (joseonmu). Joseon radish is similar to daikon, but denser and squatter, and considered by Koreans to be more flavorful. While kkakdugi is now typically seasoned in a way similar to baechu kimchi, the density and natural sweetness of the vegetable itself make its fermented version a good pairing with softer and more savory foods, particularly dishes like seolleongtang (ox-bone soup) or kalguksu (knife-cut-noodle soup).

Ideally, "it should have even more sweetness" than other varieties for balance, Park says, though others emphasize the importance of its acidity.

"I'd usually want it with a little bit of a kick, a little bit more acid to it—a little bit more age," says Hong. "Kkakdugi is rarely something I eat straight up; I'm eating it with a really rich broth of steeped bones or whatnot, and I want it there to cut that fat."

But, while its flavor is important, "it's more of a texture thing for me," says Hong, echoing the sentiments of other chefs. The size of the radish pieces is critical: Most recipes advise cutting the radish into cubes of around an inch in size, which Hong says allows the radish to gain "a little bit of give" during the fermentation process, while keeping "some integrity of the daikon."

Nabak and Dongchimi (Water Kimchi)

One of the most unique varieties is mul kimchi, or water kimchi, which more closely resembles a cold soup than anything else. Slivered or whole vegetables, like radish and scallion, along with fruits like pear, are served in the same briny broth in which they're fermented.

The most popular varieties are nabak, served in the warmer months, and dongchimi, more commonly served in the winter. The former is fermented with small amounts of gochugaru, which tinges the broth pink. Since the radishes are slivered, they lose their crispness quickly, making this a fresher variety that was traditionally made to celebrate the emergence of fresh spring vegetables after months of eating stashed baechu kimchi.

Dongchimi, on the other hand, lacks any pepper, making it a type of baek kimchi. But because it uses whole radishes, it keeps longer, so it's one of the few varieties other than baechu kimchi that are produced during kimjang, to last during the colder months.

Like baek kimchi, varieties of mul kimchi are prized as a cooling accompaniment to dishes with more heat—both temperature-wise and capsaicin-wise—or heaviness, like bulgogi (marinated and grilled beef or pork). But, in contrast with many other varieties, the ingredients in mul kimchi, particularly dongchimi, often take a backseat to the liquid in which they're fermented.

"Dongchimi for me—it's all about the broth," Hong explains, adding that it's not uncommon, on a scorching-hot day in the summer, for Koreans to pack dongchimi broth in thermoses.

"My favorite application, believe it or not, is making a granita out of it and topping it on oysters," Hong says. "It's cool because that acid and a lot of that kick acts like a natural mignonette, and that oyster gives it a little umami and flavor, and it's a great natural balance for what dongchimi is, and what the oyster naturally brings to it—that evenness, that brininess."

Where to Buy

While most Korean chefs worth their salt create their own kimchi, both Hong and Park have suggestions for those interested in trying different varieties. Above all, Hong recommends Tobagi kimchi, the house brand at the nationwide Korean grocery store chain H Mart, which was where he had his moment of kimchi theophany. He singles out Tobagi's kkakdugi for particular praise. Hong also endorses the baechu kimchi and dongchimi from New York Kimchi, which has an outpost in Manhattan but ships nationwide. Though he emphasizes his efforts to eat only the kimchi made at his restaurant, in a pinch, Park will pick up Jong Ga-jip Kimchi, one of the biggest mass-market Korean brands that are available from H Mart.