What is it?

Rice koji is ordinary rice that has been steamed and then inoculated with the fungus Aspergillus oryzae. During fermentation, this fungus converts starches into sugars and proteins into amino acids. This process is crucial for developing umami.

Use in the kitchen

• Basis for miso (white and red varieties)
• Indispensable when brewing sake
• In mirin and soy sauce
• Sometimes used in marinades (e.g., shio-koji) to tenderize meat

Flavor Profile

Neutral to slightly sweet, but mostly functional: it brings enzymes that enable fermentation.

Variants / Differences

In addition to rice koji, there are barley koji (mugi koji) and soy koji, depending on the base ingredient.

What is the difference between rice koji and regular rice?

Ordinary rice is merely boiled or steamed, while rice koji is inoculated with the fungus Aspergillus oryzae that enables fermentation.

What do you use rice koji for?

For the production of miso, sake, mirin, soy sauce and marinades such as shio-koji.

Can you make rice koji yourself?

Yes, but this requires knowledge and strict hygiene. Usually rice koji is purchased ready-made.

Is rice koji healthy?

Yes, it contains enzymes that promote digestion and is rich in natural umami.

Where can I buy rice koji?

In specialty Japanese stores, some organic stores or online (usually frozen or dried).