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Koji Salt

Koji salt is a seasoning
used in Japanese cooking


  • 20 oz. Cold Mountain Koji, firm granular rice (available at Mitsuwa)
  • 1/2 cup and 1 heaping Tbsp. sea salt
  • water


  1. Day one: Mix Koji rice and sea salt in a glass bowl with a clean spoon. Then, add 2 1/2 cups of water (tap or distilled water is fine) and mix well. Cover bowl with plastic wrap, leaving a small opening. Let it sit on the counter at room temperature overnight.
  2. Day two: Add 1 1/4 cups water and mix well. Cover again with a small opening.
  3. Day three: Mix with a clean spoon and cover bowl again, leaving a small opening. Repeat this step for 7 more days. It should take 10 days total. During hot summer weather, you might need to only repeat this step for 3 to 4 days because the warm weather speeds up the fermentation process. When the granular rice becomes somewhat soft with just a little bit of remaining firmness, the Koji salt is ready to use.
  4. Store the Koji salt in a jar. Freeze or refrigerate. It should last for 6 months in a refrigerator. It will continue to slowly ferment in the refrigerator.
  5. Use just like salt. It is not good to use with starchy foods like rice or potatoes, unless you eat it right away. Koji breaks down starch and turns it into liquid.
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