Place the koji in a bowl. Add salt, and then massage the koji by hand. Then, add water to stir.

Pour the mixture into a jar and loosely cover it with a lid, allowing some airflow. Let it mature in a cool, dark place for one to two months (or a little longer in winter). (If using Terada Honke’s KAMUTACHI, a specially prepared koji made from sprouted brown rice, reserve two to three months because the fermentation process takes longer.)

For the first one or two weeks, stir it once a day in summer, or every four to five days in winter. Once the koji ferments to a certain extent and you start smelling alcohol, you can stir less frequently, once a week or so. The shio-koji will be ready to be used when the fermentation becomes inactive and when both the taste and flavor settle in.

If you are using brown rice koji, the fermentation process can be accelerated by blending the mix to your preferred texture with a blender, etc.