Shoyu-koji (Soy sauce koji)

Japanese: 醤油麹（しょうゆこうじ）

Seasoning fermenting koji with soy sauce. Combines soy sauce umami with koji enzymes.

Pour soy sauce over rice koji and ferment 1-2 weeks at room temperature. Koji enzymes generate additional umami, creating deeper flavor than regular soy sauce.

Stir daily. When koji softens with slight thickness, it is ready. Drizzled on rice with egg or tofu, the expanded umami is immediate. Try alongside shio-koji to broaden your repertoire. Changing soy sauce type changes the flavor. Dark soy yields bold taste; white, elegance. Basic ratio: 200g koji to 200ml soy sauce. Keeps three months refrigerated.

Related words

Enzyme

A protein that accelerates chemical reactions in living organisms. Acting as a catalyst, it breaks down or synthesizes specific substances without being consumed itself—the key player in every stage of fermentation.

Shio-koji (Salt koji)

Versatile seasoning from fermenting koji, salt, and water.

Soy Sauce (Shoyu)

A liquid seasoning made by fermenting soybeans and wheat with koji mold in brine. It harmonizes umami, sweetness, acidity, and saltiness as a foundation of Japanese cooking.

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