Koso-zai Toka Yondan (enzyme-saccharified fourth addition)

Koso-zai Toka Yondan (enzyme-saccharified fourth addition) is a variation of yondan-jikomi, the practice of making a fourth addition to the moromi, and is used mainly in the sake brewing process. In this method, a commercially available enzyme preparation is added to steamed rice to promote saccharification. Saccharification refers to the process of converting the starch contained in rice into sugars, which give sweetness. This saccharified rice is added to the moromi (fermentation mash), the mixture in which fermentation takes place, creating a foundation for the yeast to convert sugars into alcohol. Using an enzyme preparation increases the efficiency of saccharification and allows for more stable fermentation, so an improvement in the quality of the sake is expected.