A new spin on Japanese tradition
Koji has long been used in Japan to make soy sauce, sake, miso and other traditional foods. Now, this ancient fermented ingredient is trending on both sides of the Pacific as restaurant chefs and home cooks see it as a convenient source of flavour-boosting umami, which is often described as a sense of savouriness.
What is koji? According to A Dictionary of Japanese Food, it is “rice, barley or soybeans infected with the mold [kabi] called Aspergillus oryzae.” Porridge-like, koji comes in a variety of forms. Shio-koji is made with salt; shoyu-koji is made with soy sauce; ama-koji is a sweetened variety.
Koji can be purchased as a prepared product (check Japanese stores or online at shopmitsuwa.com) or you can purchase dried koji and ferment it yourself; instructions are online from various sources.
“It is a very old naturally fermented food, that’s gotten very popular in Japan in recent years as a natural source of umami as well as beneficial flora for your digestive system,” writes Makiko Itoh, a food writer and blogger, in an email sent from her home in Vaison-la-Romaine, France. “It’s great to use in marinades for meat, poultry or fish.”
What does koji taste like? I tried both Kanekichi’s Kojiya brand salt and soy kojis. The salt koji looked like an offwhite lumpy sauce. The aroma was slightly briny, the taste more emphatically salty and bright — like the flavour equivalent of an exclamation point. The soy koji was smoother and had a salty, caramel-like flavour. It reminded me of a Chinese bean paste but with less obvious salt. Again, a very bright-tasting product.
Itoh uses salt koji to create a quick sauce made from canned tomatoes. The ingredient “enhances the umami in the tomatoes and gives the sauce a ‘meaty’ flavour without adding any meat,” she writes.