Koji is prepared with steamed grains (rice, barley, soybean) on which "Aspergillus Oryzae" (koji mold) is planted. It is matured under the certain temperature and humidity conditions which make the fungus breed easily. The spore size of Aspergillus Oryzae is 3 ~ 10 μm (※1μm＝0.001mm).
Among the various types of mold, the people in the old days had found the koji mold and made good use of it for making miso, soy sauce and sake. Now the mold has been essential for our everyday-life.
Besides, in 2006, as "it is the important asset which have been grown and used by our precursors", Aspergillus Oryzae has been designated to a "National Fungus" by Brewing Society of Japan.
This is a character invented in Japan meaning rice koji.
Made from a combination of characters for rice (米) and flower (花), this character for koji derives from the way koji fungus grows like flowers blooming.
This character comes from China, and is used for koji in general, whether made using rice, wheat, soy beans or another grain.
Used mainly in the production of miso, soy sauce, sake and koji amazake. The spores are yellow, yellowish green or yellowish brown in color.
Used primarily in the production of shochu. The spores are brown in color.
Used principally in the production of awamori. The spores are blackish-brown in color.
Used in production of tofuyo, hongju and laojiu. Makes a bright-red-colored koji.
Used in the production of katsuobushi.
Absorbs residual moisture within dried bonito, generates umami substances and breaks down fats and oils.
Rice koji becomes the ingredient for rice miso, sake, mirin, vinegar and amazake.
Wheat koji becomes the ingredient for wheat miso and shochu.
Soybean koji becomes the ingredients for mame-miso (soybean miso).
Koji amazake is a simple drink made from rice koji and steamed rice that has been enjoyed in Japan since olden times.
By mixing rice koji and cooked rice, the starch in the rice saccharifies to make natural sweetness. Also known as “the drinking IV,” nutritious koji amazake was enjoyed as a summer drink by people of all ages in the Edo period (1603–1868). Koji amazake made with rice koji contains 0% alcohol and no added sugar. It can be drunk safely by babies from 10 months old, as well as pregnant and lactating women.
There are two kinds of amazake, which are produced in different ways. While Uonuma Jozo makes amazake from rice koji, the other kind of amazake is made from the lees leftover from sake production. The one from the sake lees is sweetened with sugar and containing traces of alcohol from its main ingredient so the composition of this amazake is different.
The result of rice koji mixed with rice and water and fermented for several hours at a temperature of around 55–60°C
(1) Contains no alcohol
(2) Contains no added sugar
(3) Highly nutritious
It is made by desolving the lees leftover from sake brewing in water, adding sugar and boiling down.
(1) Contains alcohol
(2) Contains added sugar
(3) Rich in protein and dietary fiber