1. What is Koji ?
Aspergillus oryzae, also known as kōji mold (Japanese: ニホンコウジカビ (日本麹黴), Hepburn: nihon kōji kabi), is a filamentous fungus (a mold) used in Japan to saccharify rice, sweet potato, and barley in the making of alcoholic beverages such as sake and shōchū, and also to ferment soybeans for making soy sauce and miso. However, in the production of fermented foods of soybeans such as soy sauce and miso, Aspergillus sojae is mainly used instead of A. oryzae. A. oryzae is also used for the production of rice vinegars. Barley kōji (麦麹) or rice koji (米麹) are made by fermenting the grains with A. oryzae hyphae.
Eiji Ichishima of Tohoku University called the kōji fungus a "national fungus" (kokkin) in the journal of the Brewing Society of Japan, because of its importance not only for making the kōji for sake brewing, but also for making the kōji for miso, soy sauce, and a range of other traditional Japanese foods. His proposal was approved at the society's annual meeting in 2006.
The Japanese word kōji (麹) is used in several meanings, and in some cases it specifically refers to A. oryzae, while in other cases it refers to all molds used in fermented foods, including Monascus purpureus and other molds, so care should be taken to avoid confusion.
What can I grow Koji on ?
Growing Koji on Rice and Grains:
Koji spores grown on Rice or grains are most commonly used to make Shio Koji, Amazake, Miso, Sake, whiskey, and Beer.
White rice in particular releases floral aromas, with a high natural sweetness achieved by the starch to glucose conversion, and spores cultivated on barley develop a Woody, meaty and smokey aroma, with less sugar.
Growing Koji on Meat
The practice of kojifing meat is comparable with making cold cuts.
At first, the meats need to be brinded in a saline base of 2-4.5% to make ensure a clean growing environment. Once the Koji mold has been successfully been grown on the Meat, the proteins will be transformed into amino acids to create flavors, whilst tenderizing the texture of even tuff cuts within Days of aging.