Kongnamul-Guk — Bean Sprout Soup with Lid Timing (콩나물국)

Pan-Korean; soybean sprouts (콩나물) have been cultivated in Korea since at least the Goryeo period and the soup appears in the earliest Korean household cooking documents

Kongnamul-guk (콩나물국, soybean sprout soup) is Korea's most widely made soup — a seemingly simple dish of soybean sprouts in anchovy stock with guk-ganjang and a few aromatics. Its apparent simplicity conceals a precise technique: the lid management. There are two schools of thought producing two distinct results. The covered lid method (뚜껑을 닫고 끓이기): a short, covered boil concentrates steam and drives off the beany enzyme that causes lingering bitterness; opening the lid mid-cook introduces oxygen that re-activates the enzyme. The uncovered method: continuous open boiling allows progressive enzyme removal over a longer period. Both work; the cooking error is interrupting the covered cook by opening the lid out of curiosity.

Kongnamul-guk's clean, slightly peppery broth pairs with the intensity of a morning rice meal or as a recovery soup after celebration — specifically consumed the morning after heavy drinking as a traditional hangover remedy (해장국, haejangguk) where its hydration and mineral content restore the body.