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Koji Starter for Shoyu (Soy Sauce Starter Culture)

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Make your own fresh, delicious homemade soy sauce with this soy sauce koji starter culture!

This culture produces a rice koji that can be used as a base for different fermentations. It is particularly suitable for making shoyu (soy sauce).

This strain of soy sauce koji comes from the traditional Japanese manufacturer Hishiroku, which has been active for 300 years.


What is Koji?

A koji starter culture is made from spores of Aspergillus oryzae, a noble mould.

This fungus is used to inoculate steamed grains (rice, barley, wheat, soybeans, beans), which are then fermented.

The resulting koji is then used to make fermented foods of all kinds, such as soy sauce, miso, amazake, mirin, rice vinegar and more.


How to Choose a Koji Starter

Different strains of koji are ideal for particular uses.

This starter is ideal for inoculating soybeans, rice and barley. It is the perfect koji starter for soy sauce (soy sauce starter culture).

This koji starter is also suitable for making miso and amazake, but you will get better results by using the appropriate koji strains for miso or amazake.



  • Ingredients: Aspergillus oryzae spores
  • Weight: 20g (can inoculate 15kg of rice before adding water)
  • Origin: Kyoto, Japan
  • Keeps for 6 months in the refrigerator. Keep in freezer to extend shelf life by 1 year. Use more if spores are older.

Customer Reviews

Based on 1 review
Jared V Kuchinsky
Perfect for shoyu

Easy to propagate. Very active once in the brine vessel. Within a couple months the product was tasting like premium soy sauce

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