Saccharification (toka)

Saccharification (toka) is a key step in sake brewing in which the starch in rice is converted into sugar. Rice itself contains no sugar, so before yeast can carry out alcoholic fermentation, the starch must first be turned into sugar. This conversion is achieved by enzymes produced by koji mold. Specifically, enzymes in the koji, such as amylase and glucoamylase, break down the starch into glucose, converting it into a form that yeast can use. Saccharification is an indispensable step in making good sake, and it has a significant effect on the efficiency of fermentation.