Yodan jikomi (yodan)

Fourth stage mashing (fourth stage)

In order to obtain ama-kuchi (sweet) sake, a fourth addition is made to the moromi after the usual three stages. This is called  yodan jikomi (fourth stage mashing) . In the final stages of fermentation, an amount equivalent to 7-15% percent of the total white rice is added before moving on to aruko-ru tenka (addition of alcohol) or other processes. Although it is not for the purpose of making the sake sweeter, the practice of oi-mizu is sometimes called mizu yodan (水四段, “water fourth stage”).

The various kinds of yodan include that using ordinary uruchi-mai rice, glutinous mochi rice, enzyme, ama-zake , shubo, sake kasu and water. In the case of the first two, steamed rice is simply added to the mash. With “enzyme yodan”, enzyme preparations are added with water to steamed rice, and this mash is added to the moromi after saccharification. Ama-zake yodan sees hot water added to steamed rice and kome-koji. Once this mix has become sweet ama-zake, it is added to the main mash.