Shio Koji in glass jars.

How To Make Shio Koji

Course: Condiments, How to
Cuisine: Japanese
Keyword: marinade sauce, shio koji
Servings: 2 (jars)
Author: Nami
Japanese Ingredient Highlight: Shio koji (塩麹, 塩糀). A century-old natural seasoning used in Japanese cooking to marinate, tenderize, and enhance umami flavor of a dish. Learn more about this all-purpose seasoning.


  • 200 g rice koji (200 g = 7.05 oz)
  • 4 Tbsp sea salt (4 Tbsp = 50 g) (salt can be 10-30% of koji quantity - Do not use table salt)
  • 1 cup water


  1. Gather all the ingredients.

    How To Make Shio Koji Ingredients
  2. In a large bowl, break and separate the koji grains into smaller pieces.
    How To Make Shio Koji | Easy Japanese Recipes at
  3. Rub the koji firmly in hands to separate into individual grains.
    How To Make Shio Koji 2 | Easy Japanese Recipes at
  4. Rub the koji until aromatic, add salt and mix all together.
    How To Make Shio Koji 3 | Easy Japanese Recipes at
  5. Add water. If necessary, add more water if it doesn't cover the surface of koji. Rub the koji with your hands.
    How To Make Shio Koji 4 | Easy Japanese Recipes at
  6. Transfer to sterilized jar(s)/container with a lid. Make sure the shio koji are submerged in water, if not, add more water.
    How To Make Shio Koji 6 | Easy Japanese Recipes at
  7. Ferment the shio koji at room temperature, mix it once a day for 1 week during summers and 2 weeks during winters (as warmth temperature speeds up the ripening process). Add a bit of water if the shio koji is too hard. It might taste salty at the beginning, but it will gradually become mild. Shio Koji will become thicker and begin to smell sweet from the fermentation. Store in the refrigerator for up to 6 months.

Recipe Notes

Koji: Majority of koji you find at stores will appear lighter in color than this brand of koji that I use, which is slightly yellow. The yellow color comes from koji mold, and some are yellow and some are brown. Depending on the brand/company, they may mix different kind of koji molds to create more complex flavor. You see more white koji in stores as they look “prettier” (source).


Recipe by Namiko Chen of Just One Cookbook. All images and content on this site are copyright protected. Please do not use my images without my permission. If you’d like to share this recipe on your site, please re-write the recipe in your own words and link to this post as the original source. Thank you.