Doenjang

Doenjang begins with meju: in autumn, soybeans are boiled, pounded and shaped into blocks, which ferment with naturally occurring molds and bacteria in a warm room and are dried in the sun the following spring. The blocks are then submerged in brine in earthenware onggi jars. After about 30–40 days the liquid is drawn off and boiled to become soup soy sauce (guk-ganjang); the softened solids are mashed with salt and left to mature as doenjang. Some households make doenjang without separating the liquid at all.

Fermented soybean sauces have deep roots in Korea. The Chinese Records of the Three Kingdoms describe the people of Goguryeo as skilled at fermentation, and the Samguk sagi lists jang among the betrothal gifts sent by Silla's King Sinmun in 683. Detailed written recipes appear in the Joseon period.

Regional and household variations abound, from quick-fermented cheonggukjang to makjang and dambukjang. In 2018 South Korea designated jang-damgeugi (jang-making) as a National Intangible Cultural Heritage, and in December 2024 UNESCO inscribed “Knowledge, beliefs and practices related to jang making in the Republic of Korea” on its Representative List of the Intangible Cultural Heritage of Humanity.

• Plant protein: Doenjang is made almost entirely from soybeans, and per 100 g it provides a meaningful amount of protein along with minerals such as magnesium and iron.
• A fermented food: UNESCO notes that fermentation in jang produces amino acids that complement Korea's rice-based diet. Traditional medicine also credited doenjang with aiding digestion — a traditional belief rather than an established finding.
• Very high in sodium: A single tablespoon can supply a substantial share of the FDA's recommended daily limit of less than 2,300 mg. Diluting it in soups and stews and pairing it with plenty of vegetables helps.
• Allergen: Contains soy; some commercial doenjang also contains wheat.