Koji
/ˈkoʊ.dʒi/noun
A mold culture, usually Aspergillus oryzae, used to ferment rice, barley, soybeans, and other foods.
Did you know?Koji’s defining mold, Aspergillus oryzae, transforms starches into sugars and proteins into savory compounds, making it a biological foundation of several traditional Japanese foods.
Etymological Timeline
Ancient China
Old Chinese
麹 / 曲
“A mold-fermented grain starter; the exact relationship between this Chinese terminology and Japanese kōji is debated.”
Early Japanese
Japanese
かむたち / kamutachi
“An older Japanese term associated with mold-grown grain and fermentation starters.”
Medieval Japan
Japanese
麹 / kōji
“Mold-cultured grains used to produce fermented foods and beverages.”
19th Century
Japanese
こうじ / kōji
“The established Japanese term for fermentation mold or its cultured grain substrate.”
Late 19th–20th Century
English
koji
“An English loanword for the fermentation culture used in Japanese and related food traditions.”