Commonly used Koji mold

1. Classification by Category
Molds used for Tane-koji(seed koji) (or molds used for koji production) are collectively called koji mold. Koji mold is classified into several different species of fungi. The typical species most commonly used is Aspergillus oryzae which is used in a variety of ways, such as for sake, miso, soy sauce, mirin, and shochu. Moreover, Aspergillus sojae is used for soy sauce, and Aspergillus luchuensis kawachi and Aspergillus luchuensis awamori are used for shochu.

2. Categories of Use
Although all are classified as the same Aspergillus oryzae, each strain has a dramatically different look. Some have flocculent surfaces, others are epiphytic over the entire surface. In addition, the spores of each strain vary slightly in color. Each strain has its own characteristics, such as fast or slow growth, high proteolytic capacity, and strong amylolytic strength. The same can be said for other koji molds such as Aspergillus soja, Aspergillus luchuensis kawachi, and Aspergillus luchuensis awamori. As a result, many fungi vary in properties while being classified under the same species. In the strain storage at our laboratory, we store thousands of species of koji mold which vary in their properties, as mentioned above, waiting for their turn to express their individual properties. Consequently, the various characteristics of the strain of each koji mold are studied one by one, to determine which has the right properties to producing sake, miso, soy sauce, mirin, etc., and are then categorized as sake koji mold, miso koji mold, etc. Only fungi, which can assuredly satisfy the requirements, are used for brewing. For instance, in the case of brewing sake, the minimum conditions are: 1) strong amylolytic strength (especially for glucoamylase), 2) low proteolytic capacity, 3) the color of rice koji is white, 4) a pleasant koji aroma, 5) good growth on steamed rice, etc. Therefore, only one outstanding property of a fungus does not necessarily qualify it for use as a Tane-koji(seed koji). Today, it may be fair to say that each fungus used as a Tane-koji(seed koji) according to purpose is an elite strain of koji mold.