koji is the Japanese term for grain or other starchy material that has been treated with koji-kin, a mold used in Japanese, Chinese, and Korean culture to ferment soybeans and make alcoholic beverages. See qu. In Japan, those beverages include sake and the spirits shochu and awamori. The mold is typically cultured on rice, from which both sake and awamori are made (awamori, native to Okinawa, is made from Thai rice), but it can also be cultured on barley, sweet potatoes, or buckwheat, the primary raw ingredients of shochu. To make koji for sake, for example, koji-kin is distributed over steamed rice in a hot, humid room called a koji muro. For two to three days, the mold is cultivated to grow evenly on the rice. In a process called saccharification, the koji-kin releases enzymes that convert the starches in the rice to sugars, which are then converted to alcohol by yeast during fermentation. See saccharification. Koji also contributes various flavor compounds to the finished beverage, as well as to fermented foods such as miso or soy sauce; one important compound is glutamate, an amino acid that imparts umami, a savoriness or depth of flavor. Koji can be classified according to the color of the mold spores that produced it (shiro/white, kuro/black, or ki/yellow), its raw material (komi/rice, muji/barley), or its end product (shoyu/soy sauce, sake). Typically, sake is made with yellow koji, shochu with black or white koji, and awamori with black koji.
Samuels, Monica. “Sake School: Koji, the Miracle Mold.” Serious Eats, February 1, 2011. http://drinks.seriouseats.com/2011/02/koji-the-miracle-mold-how-sake-is-made.html (accessed February 18, 2021).
“Understanding Shochu.” Japan Sake and Shochu Makers Association website. http://www.honkakushochu-awamori.jp/english/understanding-shochu/ (accessed February 18, 2021).
By: Lauren Clark
A double coaster for the tulip glass of genever and the short beer that make up a Kopstoot. Source: Wondrich Collection.