Tsukihaze (koji mycelium penetrating the rice interior)

Tsukihaze refers to a particular state in which koji mold (kojikin) has propagated on steamed rice. It is characterized by mycelium that is not very visible on the surface of the rice and instead penetrates deep into the interior. Specifically, the mycelium has firmly entered the inside of each rice grain, and this state is regarded as especially suited to ginjo sake and to sake with a Tanrei (light, clean) profile. This condition is an important indicator when assessing koji quality, and it is also called tsukihaze koji, a term for koji in good condition. Tsukihaze involves two concepts, haze-mawari and haze-komi. Haze-mawari refers to mycelium spreading over the surface of the koji grain, while haze-komi means that the mycelium has penetrated into the grain's interior. Tsukihaze koji is considered ideal for brewing ginjo sake, and many sake breweries, including Hakkai Jozo, make a point of using this type of koji for all of their sake.