Koji

Aspergillus oryzae or “koji” is a noble mold that is ubiquitous in Japanese cuisine. It has a superpower: it nibbles complex sugars (such as starch) to convert them into simple sugars (such as glucose). This “saccharification” action makes it possible to produce sake, rice vinegar, soy sauce, miso paste, and many other Japanese specialties.

There are three main families of koji: yellow, white, and black. Yellow is used to make sake, white for shochu and black for awamori. Mixed with rice, salt and water, koji also becomes a natural flavor enhancer: shio koji.

Like so many other pillars of Japanese cuisine, koji in its culinary form originated in China. However, the Japanese seem to revere this little mold more than anyone else. The Japanese government even declared it the “national mushroom” in 2006… And local scientists have kept its genome secret for decades. A source of national pride.