Joseon Ganjang vs Yangjo Ganjang — Traditional vs Brewed Soy (조선간장 vs 양조간장)

Joseon ganjang's origin is inseparable from meju fermentation history; yangjo ganjang production was formalised in 20th-century Korea following Japanese brewing techniques introduced during the colonial period (1910–1945)

Korea has two fundamentally different soy sauce traditions that serve different functions. Joseon ganjang (조선간장, traditional soy sauce) is produced as the liquid byproduct of doenjang fermentation: meju bricks dissolved in brine, fermented 40–60 days, then the liquid (ganjang) separated from the solids (doenjang). It is saltier (22–25% sodium), darker, more complex, and uniquely savoury — a byproduct of the jang tradition. Yangjo ganjang (양조간장, brewed soy sauce) is a separate production from defatted soybean cake + wheat, brewed for 6 months, with a milder salt (16–18%) and sweeter character — the style that drives commercial Korean and Japanese soy sauce production.

The choice of soy sauce is the invisible variable in Korean cooking: the same recipe made with guk-ganjang versus yangjo produces noticeably different depth and colour. Korean cooking students who master this distinction immediately cook at a more sophisticated level.