Written and illustrated by Misa Ono
To make soy sauce, you will need soy beans and barley koji, mix them with salted water and stir it for some time while resting for as long as a year. …A year!? You’d better just buy soy sauce. However, there is a seasoning you can easily make at home if you have koji. That is called “Shio-koji (salted koji)”. All you need to do is to mix koji, salt and water together, and wait for 1 to 2 weeks. So what is Shio-koji?
In northern areas of Japan, people have been cooking vegetables, meat and fish pickled in Sagohachi-zuke(*), similar to Shio-koji. At that time, Shio-koji was not used by a lot of people and not widely known in Japan. I remembered I had read a manga talking about shio-koji when I got interested in koji, and tried to make it myself. In the manga, it says, mix kome-koji (rice koji) and salt well and then add water. Stir once a day, and after 1 to 2 weeks when it comes to smell like fermented banana, it is ready. Banana…? I wondered what kind of seasoning it would be. But I made it as it said anyway.
10 days later, it became something sticky that I could say looked like… banana. Because I just followed what the manga said, I had no idea what it was supposed to taste or look like. I tried pickling chopped cucumber with the shio-koji sealing them into a plastic bag, and rested it in the refrigerator for 30 minutes to one night. This is the ordinary pickling process. However, with the shio-koji, the taste had more umami and profoundness. I almost thought I was genius to make such delicious pickles in such an easy way. And then I tried with chicken in the same way and cooked it. The meat was tender and delicious with umami. At that moment, I was too amazed by what I had just made and didn’t care if it was a right shio-koji. I ended up publishing a cooking book with shio-koji. After that, the shio-koji boom has broken out in Japan.
(*sagohachi-zuke (358-zuke) is a pickling bed made of salt, koji and rice the ratio of which is 3 to 5 to 8. Sweeter and thicker than rice-koji.