Miso is a condiment made from fermenting soybeans with salt and koji (fermentation starter). It can be used in soups or "nabe" (refers to a variety of communal hot-pot meals) or even brushed on grilled eggplant. Miso is categorized into different types depending on the ingredients used:
- Kome Miso
Kome miso is made with soybeans and rice koji, and is about 80% of what is currently produced in Japan. There are six kinds with different flavors and colors including sweet miso (white or red), mild miso (yellow or red), and salty miso (yellow or red). Sweet miso that uses boiled soybeans with a high proportion of rice koji is known as white miso, and is often used in dishes such as saikyo-zuke (fish pickled in miso).
- Mame Miso
Mame miso is made primarily in Aichi prefecture by fermenting soybeans and salt only over a long period of time. It is also called red miso from the reddish, dark brown coloring, and is known for having a rich flavor and tartness, with a slight hint of tanginess.
- Mugi Miso
Mugi Miso is made with soybeans and barley-based koji, and has a distinct aroma of barley and light sweetness.

The main ingredient in miso, soybeans, is rich in vegetable proteins and dietary fibers. The fermentation process also produces a lot of amino acids, vitamins, and minerals. It is also rich in soy isoflavone which functions similarly to female hormones.

Refrigerating is recommended as temperature changes can have an adverse effect on miso.

It is said that the birth of soy sauce production in Japan derives from making Kinzanji temple miso, miso produced in Wakayama prefecture. The liquid condensed at the bottom of the miso casks during the production process was used in cooking as a seasoning and brought out the deliciousness.
In recent years, other varieties of beans have started to be used to make miso, such as garbanzo beans, green beans, adzuki beans, and black soybeans.