Tane Koji, or Koji Starter, which comes in a 20g sachet of aspergillus oryzae (麹) is a filamentous fungus used in Japanese cooking to saccharify rice for sake and amazake, to ferment soybeans for soy sauce and miso and a wide range of other food products. It is also used to produce rice vinegars and is an integral part of some of the world's oldest fermentation traditions.
The variants available are:
米麹用 – Rice Koji starter
麦麹用 – Barley Koji starter (for miso)
豆麹用 – Beans Koji starter (for miso)
醤油麹用 – Soy Sauce Koji starter
One sachet is enough to inoculate 10kg of rice, beans or barley.
Please note: this is the starter used to make rice koji, it therefore still needs to go through a fermentation process, which requires some time and equipment. Koji starter has a limited shelf life and should be used within three weeks of opening.
Kojiya Sansaemon is a 600-year old, 29th generation family business and one of the oldest businesses in Japan producing koji products. They are based in Kyoto.