So, what is koji? Koji is a fermented mixture of sea salt and koji rice spore. It is used as a popular Japanese condiment as well as the base for many traditional Japanese foods, most notably miso. But to really explain what koji is, we’d like to tell you about how we make it.
The base recipe for our miso products is rice koji, non-GMO soybeans, and salt. Koji plays an incredibly important role in the creation of miso. Marukome has made it our mission to share Japanese koji in the form of miso, because we believe that everyone should experience the health benefits that have been part of Japanese culture for so long.
Our shio koji and shoyu koji are also great ways to get some of the health benefits found in miso. You can use these as condiments or as ingredients in many recipes, such as stir fries, koji soups, and marinades.
Making koji is a somewhat sacred process in Japan because of the many healthy qualities it is believed to possess. For example, one of the lesser known healing properties it is said to possess is making your skin smoother. For as long as people have been making koji, it’s been observed that those who handle it have incredibly smooth skin from close contact with its ingredients every day.
Making koji starts with koji-kin, a type of mold that is commonly used in Chinese, Korean, and Japanese culture to ferment foods and make alcohol. Koji is made by sprinkling koji-kin over steamed rice and allowing it to incubate for about two days. The koji-kin ferments and breaks down the steamed rice, adding a unique sweetness while simultaneously releasing important amino acids such as glutamate. This creates umami, the savory depth of flavor that you can taste in miso.
While koji is sometimes consumed by itself as a condiment (as shio koji or shoyu koji), it is most often used to make other healthy food items.
The fermentation process gives koji most of its healthy properties. During fermentation, probiotics are created, increasing the good bacteria that your stomach needs to work properly. These good bacteria also help you maintain a healthy immune system. Additionally, koji inhibits the absorption of cholesterol, making it a heart-healthy food. When koji is added to soybeans in miso-making, the further fermentation process creates even more health benefits—some studies suggest, for example, that miso acts as a cancer preventative.