Chunggukjang — Quick-Fermented Soybean Paste (청국장)

Chunggukjang belongs to the winter table of the Korean household, where cooked soybeans were fermented in the warmth of the ondol room and eaten within days rather than matured for months as doenjang is. The name is commonly read as 'paste of the Qing', and some food historians also point to an older, looser sense of cheong-guk as a foreign country; the name is therefore taken to suggest a link with the continental mainland, though the route is not settled. The Joseon household manuals treat fermented soybean preparations as a staple of the pantry, and chunggukjang has remained a domestic food, made in the home and carried by farming families through the cold months.

Chunggukjang (청국장) is the quick-fermented soybean paste of Korean cooking: whole cooked soybeans (Glycine max) fermented for two to three days at 40–42°C (104–108°F) by naturally occurring Bacillus subtilis, which yields a pungent, ammonia-scented paste with long white threads stretching through the beans. Unlike doenjang, which matures for months in earthenware, chunggukjang is made within a few days. It is chiefly cooked as chunggukjang jjigae, a strongly flavoured stew that divides households between those who grew up with it and those who cannot bear the smell.

Chunggukjang jjigae is the principal use: the paste is dissolved in anchovy stock and simmered briefly with tofu, kimchi and vegetables. The smell deepens during cooking and fills the room. It is eaten with plain rice, whose mild, soft character steadies the pungency and salt of the stew and gives the palate somewhere to rest between spoonfuls.