Miso

Miso is a traditional Japanese seasoning produced by fermenting soybeans with salt and koji mold (Aspergillus oryzae), often combined with rice or barley. The koji culture is the same mold used in the production of sake and soy sauce.

The most common varieties include white miso (shiro miso), which is milder and fermented for a shorter time, and red miso (aka miso), which has a stronger, saltier flavor from longer fermentation. Other regional types include mixed miso (awase) and barley miso (mugi miso).

The earliest written records of miso in Japan date to the Nara period (710–794 CE). The fermentation technique is believed to have been introduced from China and adapted over centuries into the distinct varieties used in Japanese cuisine today.

Culinary tradition advises against boiling miso, as high heat can kill the beneficial microorganisms and diminish the complex flavors developed during fermentation. Most recipes recommend dissolving miso into warm but not boiling broth at the end of cooking.