Koji Rice Japanese Fermentation Starter 1kg

Koji rice (also called kome-koji, 米麹 in Japanese) is cooked rice inoculated with Aspergillus oryzae, a beneficial mold used in many traditional Japanese fermentations. During a controlled incubation period (usually 2–3 days), the mold grows over the rice and produces powerful enzymes—particularly amylases (which break down starch into sugar) and proteases (which break down protein into amino acids like glutamate).

Key Characteristics:
Base ingredient: Usually white polished rice, sometimes brown or other grains.

Fermentation agent: Aspergillus oryzae (a GRAS-rated mold in food production).

Enzymes produced: Amylase, protease, lipase, and more—essential for breaking down complex food components.


Common Uses:
Koji rice is the enzymatic engine behind many iconic fermented Japanese foods:

Miso – Koji rice + soybeans + salt

Sake – Koji rice + steamed rice + yeast

Shoyu (soy sauce) – Koji rice + soybeans + wheat + salt water

Amazake – Koji rice + water (sweet, non-alcoholic)

Shio Koji – Koji rice + salt + water (a marinade and seasoning)


Why It Matters:
Koji rice is not just a moldy grain—it’s a bio-reactor that breaks down food into simpler, more flavorful, and often more digestible components. It creates deep umami, sweetness, and aroma, making it invaluable in traditional and modern culinary applications.


If you’re interested in making or using it, let me know—I can guide you through the process or help you experiment with unique applications like koji-aged meats, koji oil, or upcycled ferments.