Meshibuta (surface condition of the fermenting mash)

Meshibuta (飯蓋) is a term describing the condition of the surface of the moromi (fermentation mash) during sake fermentation. As fermentation progresses, various kinds of foam form on the surface of the moromi, and meshibuta refers specifically to a state in which the surface looks as though grains of rice are floating on it. This state is regarded as a good sign that the fermentation of the moromi is proceeding smoothly. In general, meshibuta appears as the foam thickens and the rice grains gather together, which shows that fermentation is under way. Such changes in the surface serve as an important indicator in the sake-making process and are one of the factors that influence maturation and quality.