Korean food is grounded in fermentation—quite literally.
Traditionally, large clay pots, called onggi, were buried underground to achieve optimal temperatures for fermenting and preserving their contents. Many different kinds of foods were and still are fermented; the process is so ubiquitous in the cuisine that Korea has been referred to as the “kingdom of fermented foods.”
Of course, kimchi is what usually first springs to mind, but that’s just the beginning. Korea’s fermenting prowess casts a wide net across food and beverages alike; in fact, according to “Korean Food, the Originality,” there are officially 336 different types of kimchi; about 160 kinds of vinegar-pickled vegetables, or janggajji; 170 varieties of salted seafoods, jeotgal; 370 different liquors; and 130 kinds of seasoning sauces, called jang.
Korea’s fermented sauces, jang, are the cornerstones of its cooking. Most dishes in Korea are seasoned with jangs, as opposed to just salt. It is these sauces that add that characteristic umami richness to Korean dishes.
Soy sauce (ganjang), chili paste (gochujang), and soybean paste (doenjang) make up the vital ruling triumvirate of Korean cuisine.
Soy sauce, made by fermenting soybeans, is used like salt, adding liveliness and depth. Gochujang, fermented chili paste, adds sweet-ish spice and heat. Doenjang (or dwengjang), the fermented soybeans leftover after making soy sauce, adds a richly savory, earthy flavor to anything it touches. All three jangs are used liberally in sauces, marinades, and soups in both “raw” and cooked forms.
Doenjang, however, is perhaps the most coveted and copiously consumed. This “thick paste” is one of the most distinguishing flavors of Korean food, contributing an unapologetically strong boost of umami—achieved through its fermentation process—to any dish. Think of it as Korea’s version of Japan’s miso paste, but on steroids—it is coarser, funkier, and more pungent in taste.
Doenjang is the key ingredient to iconic dishes like doenjang jjigae, a savory stew that commonly graces the Korean table in bubbling cauldrons, and ssamjang, a hot sauce slathered on Korean barbecued meats.
How Doenjang Is Made
The process starts with soybeans that are harvested in the autumn, when they are fully ripe. The beans are soaked and boiled in large iron pots for three to four hours, until soft, and then pressed into rectangular blocks, which are left to partially dry in the shade.
Next, the blocks are tied and hung with straw to ferment for a few months. The bacteria in the straw and the air aid in the fermentation process naturally. The blocks grow moldy and eventually dry fully into hard bricks, called meju.
Soy sauce is produced by soaking these bricks in salted water in onggi, large traditional clay pots, to age for six months. Doenjang is then made by further fermenting the remaining pieces of meju, after the soy sauce has been drained away.
For both products, the aging process is key. The final flavor depends greatly on the type of clay jar used to age them, their exposure to sunlight, and even the quality of the air and wind.
To soak the meju for soy sauce, only brine made from the purest water and sea salt should be used, and in very specific proportions. In the olden days, Koreans believed that using the water from melted snow from the last lunar month enhanced the flavor, and pots made of clay collected in July were the best. Other ingredients are now also added: red peppers, jujubes, and charcoal (to prevent odors and to ward off evil spirits).
After anywhere from 2 to 5 months, depending on the weather, the meju is removed from the liquid, which will have turned brown from the amino acids breaking down—this is soy sauce.
The meju is then further salted and left to continue fermenting for another month or two. The onggi lids are removed and mesh cloths are tied over the tops, to expose the paste to sunlight. This step requires special attention and care, as the level of bacteria must be monitored to prevent it from rotting.
Depending on the desired strength of the doenjang’s flavor, it can be aged for a longer or shorter amount of time.
Nowadays, doenjang is mass produced commercially, and often full of artificial flavors, stabilizers, and other substances used to speed up the fermentation process. There are some artisan producers, however, that are keeping the traditional way of making doenjang alive.
Hyena Kwon’s family has been making doenjang the old-fashioned way for decades under their brand Korea Macgguroom, or simply “Mac,” which means “carrying on the traditional legacy.” The company was started in 1989 by Kwon’s mother, Seong Myeong-rye, who was awarded the title of Grand Master of Traditional Foods by the Korean government in 2012. She acquired a secret recipe for doenjang from her mother-in-law, who hailed from Andong.
The Kwons specialize in a type of doenjang called gyep (“layered”) doenjang. It is considered layered because after six months of fermenting in the brine, once the resultant soy sauce is drained off, more dried meju bricks are added in along with fresh brine. The salinity level is monitored closely to ensure that it does not decay. This double meju mix is then left to ferment for about a year longer.
They also cover their doenjang jars with only white cotton cloths, never lids, and place them in large greenhouses, to allow the doengjang to breathe and be exposed to the sun. The Kwons believe that air and sunlight are important ingredients for ideal fermentation, and even place river rocks in the bottom of their pots to ensure proper air circulation around the paste. The resulting doengjang is stronger and richer in flavor, and full of umami.
Mac Doengjang is fermented for about 16 months total, in onggi that have been used and seasoned for more than 30 years, collecting unique bacteria in their pores over the generations. In 1989, the Kwons started out with about 20 jars, and now they have more than 3,000. The unique flavor these onggi impart to their doenjang is one built up over so many years, and cannot be replicated.
Fortunately, the demand for classic doenjang is strong and growing, as people’s tastes move back to tradition. As a result, small artisan producers like Mac Doenjang are thriving.
Cooking With Doenjang
Doenjang is prized because it does not lose its unique flavor when mixed with others, and it only gets better with aging, like a fine wine.
There are so many different ways to cook with doenjang, but it is most commonly used in soups and stews. Doenjang jjigae is one of the most popular dishes, served at home and in restaurants alike.
Most families have their own recipe for this satisfying bowl; I prefer to make it with clams. You should always serve it in an earthenware bowl, ttukbaegi, which enhances the stew’s richness and rustic flavor.
Judy Joo is a chef, restaurateur, author, and TV personality. Her newest book is “Judy Joo’s Korean Soul Food.”