- Mixing (with a kai tool)
The term for mixing the ingredients of shubo and moromi ( water, koji and steamed rice ) with a long, oar-like tool called a kai or kai-bo (long “o”). Mixing is carried out to balance the liquefaction and fermentation of the mash. The various ways of mixing listed below are used as necessary according to the state of the moromi (the progress of fermentation and the hard-or softness of the steamed rice).
Kuriage-gai ( 繰上櫂, “lifting kai” ). The tool is gently put into the mash on the nearside of the tank, and pulled upwards along the side of the tank to bring the ingredients from the bottom to the surface of the mash.
Tsuki-gai ( 突櫂, “pushing kai” ). The kai is pushed into the mash diagonally to the far side of the tank, then gently pulled back and lifted out. Because it is encourages fermentation without lowering mash temperature, it is also known as wakashi-gai ( 沸かし櫂, with the character 沸 meaning to ( make ) boil ). This method is the one mainly used in the period from mashing until ochi-awa.
Hiki-gai ( 引櫂, “pulling kai” ). Starts with the opposite motion to tsuki-gai, pushing the tool away through the mash, before pulling it back to mix vigorously. Also known as samashi-gai ( 冷まし櫂, “cooling kai ), as it lowers mash temperature, this technique is the most used after the tama-awa stage.
Ran-gai ( 乱櫂, “rough kai” ). Rough mixing intended to break down the raw materials.
Soko-gai ( 底櫂, “bottom kai” ). Mixing in order to lift the section of the mash which has settled at the bottom.
Mukae-gai ( 迎櫂 ). A gentle mixing intended to promote fermentation by loosening clumps of steamed rice and bringing it to the surface.
Wari-gai ( 割櫂, “splitting kai” ). Promoting fermentation at the soe stage by breaking the raised, swollen surface of the mash with a cross shape before kai-ire proper.
Ippon-mairi ( 一本参り ). When one worker lightly mixes each tank of moromi.