Nuka (rice bran)

Nuka is the outer layer and bran layer of rice that are removed when rice is polished, and it plays an important role in sake brewing. As the rice polishing ratio becomes higher, the portion closer to the center of the rice remains and the amount of nuka decreases. Nuka is classified by particle size and color, and is generally divided as follows: nuka from rice polished to a ratio of around 90% is called "aka nuka" (red bran), up to around 85% is "chu nuka" (middle bran), up to around 75% is "shiro nuka" (white bran), and anything beyond that is called "tokujo nuka" (premium bran) or "toku shiro nuka" (extra-white bran). Nuka is rich in nutrients and is used as fertilizer and animal feed, and it is also sometimes used as an ingredient in health foods.