I decided to explore a bit further and began some research into the matter. So, follow, if you will, for a short sake-making history. It was invented in Japan probably sometime around 300 A.D. which is when it first shows up in written records. Because of the complexity of its brewing, in the early days it was generally reserved for royalty or ceremonial occasions. There are seven sake brewing plants in the Western United States so located because California is the source of most US rice, the climate is right, and there is plenty of good water.
Rice is washed and steam-cooked . . .
The whole mix is then allowed to ferment, with more rice, koji, and water added in three batches over four days. This fermentation, which occurs in a large tank, is called shikomi. The quality of the rice, the degree to which the koji mold has propagated, temperature variations, and other factors are different for each shikomi. This mash is allowed to sit from 18 to 32 days, after which it is pressed, filtered and blended. This is only the beginning of the story, believe me.