Amazake
Japanese: 甘酒
A sweet drink made by saccharifying rice starch with rice koji. Two types exist: non-alcoholic koji amazake and kasu amazake made from sake lees.
Koji amazake is made by holding rice koji and water at 55-60 degrees Celsius, allowing koji enzymes to break starch into glucose. This naturally sweet drink is so nutritious it has been called a drinkable IV. Rich in glucose, amino acids, and B vitamins, it was popular during the Edo period for summer fatigue. It is the simplest way to taste fermentation in a single cup. Kasu amazake dissolves sake lees in hot water with added sugar and contains trace alcohol. Koji amazake and kasu amazake are entirely different drinks. Recently, koji amazake is also used as a sugar substitute.