Kasu (sake lees)

Kasu (粕) refers to a by-product of sake production, chiefly sake kasu (酒粕, sake lees). In brewing, rice and water are fermented to make moromi (fermentation mash). When the moromi is pressed, the liquid from the upper layer becomes sake, and the solids left in the lower layer are the kasu. Sake kasu is highly nutritious and is also used as a food ingredient, most often in miso, pickles, and kasuzuke (foods pickled in sake lees). Kasu also has a distinctive flavor and can add depth to dishes.