Ki-moto 生酛

Ki-moto is one of the traditional methods used to develop the sake starter and often involves highly labor intensive yamaoroshi (pole ramming) to create a smooth paste. (There is no regulation requiring this more traditional yamaoroshi method in ki-moto, but it is often preferred.)

Steamed rice, koji and water are mixed in a small batches at a temperature of around 7℃. After the water is absorbed (around 5 – 6 hours), the batches are mixed with a wooden paddle every 2 – 3 hours to prevent microorganism growth on the dry surface.

After 10 – 15 hours (3 – 7 mixings), the steamed rice and koji become soft and inflated, and the yamaoroshi pounding is started. This process is normally conducted three times(every three hours). It is often done with a wooden pole, but some sake breweries smash rice by foot instead. The purpose of this process is to extract the koji enzyme for saccharification.

 After the pounding, all of the small batches are combined in a bigger tank.

Once the natural lactic acid reaches a certain level, cultivated yeast is added. Finally the brew master (toji) controls the temperature of the mixed liquid for ideal propagation of yeasts and this starter is left to develop for approximately 30 days. (If the yeast is not added (ie if the toji uses live airborne kuratuki-kobo yeast, the starter needs around 50 days to develop.) 

Ki-moto often creates a very rich umami and full-bodied sake with cheese or steamed rice flavors and a longer, complex after taste.