Haze (Koji penetration)
Haze
Japanese: 破精（はぜ）
The penetration of koji mold hyphae into the substrate (such as steamed rice). The depth and uniformity of penetration greatly affect koji quality.
Haze refers to the phenomenon of koji mold hyphae penetrating into the interior of steamed rice. Beyond merely growing on the surface, the hyphae extend toward the core of each grain. The degree of this penetration determines koji quality.
Deeply penetrated koji allows enzymes to reach throughout the rice, enabling efficient saccharification and protein breakdown. Shallow penetration means enzymes cannot fully exert their power.
In sake koji-making, the pattern of haze penetration is one of the most critical factors influencing flavor. Both 'total penetration' and 'spot penetration' have their respective uses. One of the important elements supporting fermentation's diversity.