Making Jang

Jang is the collective name for Korea's fermented soybean seasonings: ganjang (soy sauce), doenjang (soybean paste) and gochujang (chili paste), among others. They season almost everything on the Korean table, from soups to namul. What sets the Korean method apart, as Korea's Cultural Heritage Administration noted when it designated jang-making a national heritage item in 2018, is that ganjang and doenjang come out of the same jar in a single process.

Step 1: Making meju

Everything starts with meju, blocks of cooked, fermented soybeans. Traditionally they were made in late autumn or early winter.

• Soybeans are soaked, boiled until very soft, mashed and pressed into firm bricks.
• The Encyclopedia of Korean Culture describes drying the bricks on rice straw for two or three days, then tying them with straw and hanging them indoors, or packing them on straw in a warm place (around 27–28°C) for about two weeks. In older homes this warm spot was the room heated by the ondol floor.
• During this time a mixed community of wild molds and bacteria colonizes the blocks, breaking down soybean protein and starch and building the savory, earthy flavor that defines jang. The bricks are then dried further, often in spring sunshine.

Because traditional meju relies on whatever microbes the household, straw and season provide, every family's jang tastes slightly different. Factory meju made since the 1960s uses selected starter cultures for more predictable results.

Step 2: Steeping in brine

The dried meju is washed and placed in a large earthenware jar filled with salt brine. Cooks traditionally float dried red chilies and pieces of charcoal on top. The encyclopedia notes these were valued both practically, for their absorbent and antimicrobial qualities, and symbolically, to ward off misfortune; a rope of straw (geumjul) was sometimes tied around the jar for the same reason. The jar then sits in a sunny spot, opened on fine days and covered in rain, for roughly a month or longer while the meju releases color, salt-soluble proteins and flavor into the liquid.

Step 3: Separating ganjang and doenjang

The pivotal step is jang-gareugi, separating the jang. The softened meju is lifted out and mashed, often with extra salt, then packed into its own jar to mature into doenjang. The dark liquid left behind is strained and traditionally boiled to become ganjang. Both continue aging for months or years.

The encyclopedia describes ganjang graded by age: younger, lighter soy sauce for soups and older, darker, sweeter soy sauce for more delicate dishes. Some families keep a long-aged ssi-ganjang (seed soy sauce) for decades, topping it up with new soy sauce each year to carry a house flavor forward.

Gochujang

Gochujang is made differently: powdered meju is mixed with cooked glutinous rice (or other grains), malt, chili powder and salt, then left to ferment. The encyclopedia identifies the mid-18th-century Jeungbo Sallim Gyeongje as containing the earliest known recipe, and early versions used far less chili than today's.

Onggi and the jangdokdae

Jang has long been fermented in onggi, unglazed or lightly glazed earthenware jars grouped on a sunny, airy platform called the jangdokdae. Korean sources describe onggi as a breathing vessel: high-temperature firing leaves microscopic pores that let air pass through the walls while holding liquid in, which is thought to help steady fermentation and storage. The Encyclopedia of Korean Culture's soy sauce entry also mentions a bamboo divider set inside some jars so the liquid and solids could be separated more easily.

History

Fermented soybean seasonings have deep roots on the peninsula. The Samguk Sagi records jang among the gifts for a Silla royal wedding in 683, and the Goryeosa notes salt and jang distributed to famine victims in 1018, a sign of how essential it had become. During the Joseon dynasty the royal court kept dedicated jang storage and staff.

Heritage status

Jang damgeugi (jang-making) was designated a National Intangible Cultural Heritage of Korea in 2018. On December 3, 2024, at the 19th session of UNESCO's Intergovernmental Committee in Asunción, Paraguay, “Knowledge, beliefs and practices related to jang making in the Republic of Korea” was inscribed on the Representative List of the Intangible Cultural Heritage of Humanity. It was Korea's second food-related inscription after kimjang. UNESCO's description emphasizes that jang is made and shared within families, passed down largely from mothers and mothers-in-law, and increasingly taught through community groups and schools.

In the kitchen

Ganjang seasons namul such as sigeumchi-namul and braises such as jangjorim and dubu-jorim; doenjang and gochujang flavor soups, stews and dressings throughout Korean cooking.