Miso (fermented soybean paste) (味噌)

Miso is a Japanese food made by fermenting grains. It is a staple seasoning of Japan, which is known to the whole world as a Japanese taste.


Today, a variety of ingredients are available for side dishes so miso is deemed to be a seasoning, but traditionally it had been the principal protein source in the Japanese diet. Today as a seasoning, it is still one of the necessities of Japanese cuisine. The main ingredient is soybean (it used to be rice bran in the Sengoku period, the period of warring states). It is mixed with koji (a fermentation agent) and salt to ferment, so the protein of soybean resolves to be easily digestible and large amounts of amino acid which is the source of umami (savory) are released. In the production of miso, the more koji, the more sweet it becomes; the more soybean, the more umami it has. It is an artisanal product made in the moderate and humid climate of Japan, but it is becoming difficult to maintain the tradition being subject to modern food hygiene standards.

There are a wide variety of miso which fall into several categories by region or kind: red miso, white miso, blended miso and so on.

Generally, the term 'miso' refers to only Japanese ones, but sometimes, based on their similarity, it includes fermented foods of the same genealogy from East and Southeast Asia, like 'jiang' (Chinese sauce): the seasoning also called 'Chinese miso.'
Sitologically and anthropologically, Japanese miso is classified as kokusho (sauce made from grain) in the salted food category.

Many Japanese badly want to drink miso soup while traveling abroad because the taste makes them feel at home.

The slow food boom and the Japanese food boom have made us revalue the benefit of miso.


Rice: rice for processing

Koji: made of rice, barley, bean and so on; showing regional variation.


Vitamin B12
Vitamin E


Miso is an original seasoning of Japan, and its original form dates back to the Jomon period.

Misho, which is considered to be the original form of miso, was written in the literature already in Nara period, and the existence of misho stores in the western market of Heian-kyo (the ancient capital of Japan in current Kyoto) is recorded. Thus it was firmly established in this country from old times. Misho is presumed to be something like bean miso of today, but it was only in later ages when koji was frequently used. It is written in a book during the Heian period that miso was used to season rice gruel.

It used to be made at home, and the term 'temae miso' (literally means "handmade miso," but the true meaning is "self-glorification") was born. In the Muromachi period, miso was developed everywhere and used as preserved food rather than as seasoning (today, when miso is mentioned, the past comes to mind, but the original miso was retained the grains of rice or barley, and was eaten with the fingers). It was useful as army provisions during the Sengoku period and was a valuable source of nutrients for soldiers. It's vestiges are still found in Hoba miso (local cuisine at Hida Takayama region, Gifu Prefecture) and in other places. Busho (Japanese military commander) around the country came to think of miso production as one of the important economic policies. During the Edo period, miso was first recognized as a seasoning just like today. Reflecting the natural features and climate of the region, a variety of miso matured in different ways was developed all over Japan.

The method for the industrial mass production of miso has been established in modern times so, now it is seldom that miso is made at home. Today miso manufacturers are in all parts of Japan, from Otoineppu-mura in Hokkaido to Yonaguni-cho in Okinawa Prefecture; it proves that miso can be produced without high technology or large capital. That is the difference between miso and soy sauce manufactures, that concentrate in certain areas.

Like other food products, miso came to be equipped with multifunction and differentiation from others; in addition to the difference of ingredients, soup stock, calcium and so on are added to miso for sale. By the 1970's, soy sauce and miso was kept in barrel and sold by measuring at grocery stores (liquor store or Mikawaya), but sale-by-measuring system disappeared with changes in the distribution system, switching to sale in packages such as bags or plastic containers. Formerly potassium sorbate was used as additive in a packaging process, but nowadays ethyl alcohol is added at two or three percent. This prevents expansion.

Classification by JAS (Japan Agricultural Standards)

According to Japan Agricultural Standards (JAS), miso is written as 'みそ' and classified as follows.


Rice miso - made by fermenting and maturing soybeans and rice.

Barley miso - made by fermenting and maturing soybeans and barley or rye.

Soybean miso - made by fermenting and maturing soybeans.

Blended miso - made by blending miso mentioned above. It also can be other kinds of miso.

Red miso and white miso

The difference between red miso and white miso is created by Maillard reaction caused by protein and sugar in soybean and koji, and mainly arises from a period of maturing. Red miso is matured for more than a year, therefore it contains salt at high concentration. Because its maturing period is long, Maillard reaction proceeds so that miso takes on a brownish color. White miso contains salt at a low concentration and is matured for as short as several months. Because its maturing period is short, its color is white and sometimes grains of ingredients such as barley or others remain. Other measures are also taken to suppress the Maillard reaction: boiling soybeans instead of steaming, or regulating the kind or amount of koji.

Red miso contains salt at high concentrations and tastes salty, and has plenty of body to it because of the long period of maturing. White miso contains salt at low concentration, and is sweet because of the sugar in koji. Red miso is produced mainly in the Tohoku region (rice) and Chukyo area (soybean). Because beans are low in sugar and high in protein which is the material for amino acid, beans are mainly processed into red miso.

Characteristics and regions of rice miso, soybean miso, and barley miso

The kind of miso which is widely distributed nationwide is rice miso, and soybean miso (red) is produced only in the Chukyo area. Rice miso varies in color from yellow to yellowish white and red. Light-colored rice miso is generally made from boiled soybeans, whereas deep-red rice miso is made from steamed soybeans. Miso made with a lot of rice koji (malted rice) tend to mature in a short period. Representative white miso made from rice are Shinshu miso (made in Nagano Prefecture) and Saikyo miso (made in Kyoto), and the representative red miso made from rice are Tsugaru miso (made in Aomori Prefecture) and Sendai miso (made in Miyagi Prefecture). Saikyo miso is very sweet, and Sendai miso is very salty. Tsugaru miso has good body, and Shinshu miso has a light taste; there are various kinds of rice miso. Rice miso is mainly consumed in all eastern Japan, Hokuriku and Kinki regions.

Barley miso accounts for about eleven percent of the total production, and the Kyushu region, west of Chugoku region, and west of Shikoku region are where white miso made from barley is mainly produced. In Kita Kanto (Northern Kanto), red miso made from barley is produced.

Soybean red miso is made from steamed soybeans (or boiled soybeans) and soybean koji. It has a longer maturing period than rice red miso, so that its color red is deeper than rice red miso: deep reddish brown tinged with black. Compared to rice miso and barley miso, it is less sweet and has a nasty bitter taste and strong umami, which are distinguishing characteristics of soybean red miso. The regions in which soybean miso is mainly consumed are limited to all of the Aichi Prefecture of Chukyo area, the south-central and western Mino Province of Gifu Prefecture, and the north-eastern part of Mie Prefecture. Representative soybean miso is Haccho miso.

In recent years, miso made from various grains such as foxtail millet, barnyard millet, and common millet, are also sold at some natural food stores.

Carcinogenicity of kojic acid

Kojic acid is a food additive which is approved for use as an existing additive, according to the revision of the Food Sanitation Law in 1995. The acid is produced by Aspergillus oryzae (the genus Aspergillus or others), which is used for production of miso, soy sauce, and so on; it is an important substance which has an antibacterial effect and prevents the ingredients from rotting. On the other hand, the carcinogenicity of miso and soy sauce became an issue when it was pointed out that kojic acid leads to the risk of liver cancer. However, kojic acid in food is resolved by microbes and enzymes upon maturing (the lack of salt allows mold to grow) and its amount in food is minute compared to its concentration in biological tests. Because animal experiments show that miso prevents the incidence of cancer including lung cancer, and it is a traditional food which has been eaten for a long time; the toxicity of kojic acid is considered to have little effect.

Although only some representative and famous kinds of miso are listed above, miso are produced all over the country. Miso varies in flavor and color by region, making them a home-grown food.

The theory about miso's health benefit

There is a theory that 'fatty acid ethyl' produced by fermentation reduces the power of mutagen which causes cancer. Results of investigation show that people who often drink miso soup have low death rate from stomach cancer.
(Japanese Cancer Association in 1981)

However, you should be careful not to consume excessive amounts of salt because miso has a lot of it.

[Original Japanese]