Haze (koji mold growth on rice)

Haze (破精, also read "hasei") refers to the white patches formed on the surface of koji rice by the mycelium of koji mold. They appear during the koji-making process as a white, cotton-like growth on the surface of the rice. Depending on the condition of the surface, haze is divided into two types: tsuki-haze (突き破精型) and so-haze (総破精型). In the tsuki-haze type, the surface appearance is not particularly conspicuous, but the mycelium has penetrated into the interior of the grain. In the so-haze type, the mycelium has spread over both the surface and the interior. Haze is an important factor in the fermentation of sake and affects its flavor and aroma, so its condition is carefully managed in sake production.