Ji (exposed surface of the moromi)

The term "ji" (地) refers to a specific state in the fermentation of sake moromi (fermentation mash). It is seen in the final stage of fermentation, when the foam on the moromi decreases and the surface shows a thin membrane resembling the inner skin of a chestnut (shibukawa), or the liquid surface becomes exposed. When the moromi reaches "ji," it has no foam at all. This state is called "bozu" (坊主) and is associated with a light, clean (tanrei) sake profile. By contrast, when steamed rice floats in the moromi and forms a lid, the state is called "iigai" (飯蓋), which is said to produce a rich, full-bodied (noujun) sake profile. During fermentation, the high foam (taka-awa) turns into dropping foam (ochi-awa) and then moves on to round, bubbly foam (tama-awa). When this tama-awa finally disappears, the surface of the moromi appears, and this is "ji." In this way, "ji" is a safe, well-advanced state of fermentation and an important indicator for moving on to the next step.