Mash lees, also known as sweet wine, liquor, or rice wine, is the product of glutinous rice after a series of fermentation, a process somewhat similar to the yogurt we are familiar with. During the fermentation process, the sweet koji (a special yeast) first breaks down the starch in glutinous Rice into glucose, and then converts glucose into alcohol through glycolysis in a hypoxic environment.

The nutritional value of mash is mainly the nutrition of its raw materials, that is, glutinousrice.