How to make Shoyu Koji


About recipe

Shoyu koji (醤油麹) is a “fermented seasoning” that combines soy sauce and koji. It adds umami, sweetness, complex aroma, and thickness to soy sauce, and can be used in various dishes. Its flavour is characterized by its umami (richness). It is said that it contains 10 times more glutamic acid, which is a flavour component, compared to salt koji.

Of course, the original taste and aroma of soy sauce are also present. However, the saltiness becomes milder, and you may feel a stronger umami flavour and sweetness. In addition, the aroma derived from koji adds complexity and richness to the taste.


  • 100g of Raw fresh koji
  • soy sauce


  1. Loosen koji and break it apart
  2. Put koji in a jar and pour soy sauce in a jar until koji are hidden.
  3. Leave it for 1 week.(During the aging period, mix it well once a day.)
  4. Put it in a refrigerator and use it up in 3 months.