The quality of sake depends on the availability of good rice.
Protein and fat are concentrated near the surface of rice grains. Because these components can impart a rough flavor to the finished sake, the rice is polished in mills to retain only the starchy core.
This is the most important process for making sake. Many sake breweries continue to make koji by hand even when other processes have been mechanized.
The alcohol in sake is a result of the fermentation of rice by sake yeasts. Before fermentation, large amounts of yeast are cultured. This is called kobo (starter culture).
After the water is acidified by the addition of lactic acid, the starter culture is added and kept in conditions where no other bacteria will grow.
Squeeze the fermentation mash and separate undiluted sake from the pressed sake cake.
Les grands sakes de Hiroshima