Kojiya Sanzaemon Koji Starter Spores Sour Black is designed for fermenting raw materials to produce koji with a characteristic dark color. It is distinguished by its high citric acid content, which helps create a stable fermentation environment. It multiplies quickly on the raw materials, reducing the risk of failed fermentation. It provides a rich array of enzymes, including protease, necessary for making soybean koji and other fermented products. The resulting koji is suitable for making amazake and a wide range of homemade fermented products.