Miso and Health:
Explanation from Abundant Nutrients of Miso to Its Expiration Date

What is miso

Miso, a seasoning that has deep relationship with Japanese eating habit.

As there are a wide variety of miso soup and miso dishes, are there people who have never tasted miso yet?

This time, we will tell you in detail from how miso is made to nutritional facts of miso.

What is Miso?

Miso is a seasoning in a form of paste that is made by adding salt and koji into steamed soybeans, rice, or barley.

Miso soup, a standard Japanese food, is the most popular dish using miso, and it's an essential part in the Japanese dining table.

Various types of miso are produced in various regions of Japan, and they are often used for local cuisine in those regions.

The History of Miso

す。The origin of miso is said to come from Chinese terms "醤" (Japanese reading: shō, Chinese reading: chiang (pronounced jang)) and "鼓" (Japanese reading: shi, Chinese reading: gǔ).

● 醤 "shō/chiang"
It is an animal or fish meat, grains, etc., crushed, then mixed with salt and sake, put in a pot and fermented. This had been existed in China since B.C.
● 鼓 "shi/gǔ"
A mixture of soybeans, grains, and salt fermented. It's said to be the prototype of miso.

There were some similar chiang foods in Japan, but it was said that the taste and quality were not so good.

The chiang that had been introduced from China seemed to have very high quality and good taste.

This chiang were only allowed to be eaten at the imperial court or noble-class people as a luxury food.

Miso that First Appeared in Japanese History

Miso first appeared in Japanese history books in year 901 (year 4 of Shōtai Era).

By this time, the production method of chiang and from China had been spreaded in Japan, and it's believed that the original seasoning of Japanese "Miso" was born.

During the Heian period (794-1185), miso was only made in small quantities, and it was regarded as a very valuable food ingredient.

It was around Edo period that miso began to enter the lives of ordinary people, and miso finally appear on the dining table of ordinary homes.

In order to increase the production volume, miso had begun to be made in various regions, and local original tastes and materials had came to be used in the producton process of miso.

Types of Miso Based On the Koji Used

Miso can be divided into three big group of types according to the raw materials used.

● Rice Miso (Komé Miso)

Rice miso refers to miso that is fermented by adding rice koji/koji rice to soybeans.
Although rice seems to be the main raw material from the name of "rice miso", the main raw material for making miso is actually the soybeans.
The reason it's called rice miso is because rice koji is used as ingredients in the making of miso.
This rice miso occupied 80% of all types of miso in Japan.

rice miso kome miso

● Barley Miso (Mugi Miso)

It is miso which is fermented by adding barley koji to soybeans.
Compared to koji rice, it's characterized by sweet taste and a slight smell of barley.
Mainly made in the Kyushu region, Satsuma Miso in Kagoshima Prefecture is particularly famous.

barley miso mugi miso

● Soybean Miso (Mamé Miso)

It's a miso made only with soybean koji and salt.
Red miso (aka miso) and Hatcho miso are examples of soybean miso.
There is also a possibility that it's added with koji rice to make the taste firmer.
This miso is also need to be fermented for at least 2 years.
It's said that this soybean miso is rather difficult to be made.

soybean miso mame miso

Basically, all misos are made from soybean.

They are divided into rice miso (komé miso), barley miso (mugi miso), and soybean miso (mamé miso) according to the kind of koji added to the soybean.

Various Types of Miso from Various Regions of Japan

Aside from the three types of miso mentioned above, miso can also be classified based on the making process of the miso which is unique to the each regions in Japan.

● Hokkaido Miso (Rice Miso)

Hokkaido miso is fermented and maintained for a longer time than normal miso-making process, because the cool area is slow in fermentation.
The taste is like spicy rice miso, with low saltiness.
It is a relatively refreshing taste.

hokkaido miso

● Echigo Miso (Rice Miso)

It's also called "floating-koji miso" (uki koji miso) since it looks like the grains of rice (koji's hulls) are floating.
Although it's spicy, the flavor and thickness are strong enough to make miso soup without making the dashi (soup stock).
Its salt content is slightly higher.

Echigo Miso

● Shinshu Miso (Rice Miso)

About 40% of Japanese domestic miso is said to be this Shinshu miso.
It has similar color to white miso, and it has some sour aroma and refreshing taste.
It is spicy and has a slightly higher salt content.

shinshu miso

● Tokai Soybean Miso (Soybean Miso)

The miso used in Nagoya's miso cuisine, which is famous for its red miso dishes, will be this Tokai Soybean miso.
In hot and humid regions, in order to protect the miso from oxidation, it's made with the technique called "miso-dama seigiku", which is the method by making the miso into small ball form first.
It becomes reddish brown and spicy soybean miso.

Tokai Soybean Miso

● Kansai White Miso (Rice Miso)

The ratio of rice koji to soybean is large, so it's very sweet and is also called "sweet miso (ama miso)".
The salt content is low and the color is pale color of light yellow.
The characteristic of this miso is its light flavor because of short fermentation period.

Kansai White Miso

● Setouchi Barley miso (Barley Miso)

Because it uses barley koji, it's a miso with a rich barley aroma and rich deep taste.
The use of barley koji also makes this miso contains a large amount of dietary fiber.
It's a spicy barley miso, with pretty low salt content.

Setouchi Barley miso (Barley Miso)

● Kyushu Barley Miso (Barley Miso)

It's a barley miso with high proportion of barley koji and is characterized by its strong sweetness.
As it has light color and grains of barley remains, it seems in Kyushu district it's used to make miso soup by straining the miso paste.
A low salt content barley miso.

Kyushu Barley Miso

Read the following article to know more details about various types of miso!
We also write a table of characteristics and nutritional facts of various misos in there.

The Types of Miso

The Types Of Miso: Red Miso, White Miso… There Are More Than You Thought!
Maybe some of you have known about red miso (aka miso) and white miso (shiro miso).
But actually, there are a lot of varieties of misos.
In this article, we will tell you the types of miso that Japanese people usually eat.

Read the article of "The Types Of Miso" here.

Health Effects of Miso

We already know that almost all of the misos are made with soybeans and koji.

It has been found in recent research that this miso, which contains both soybean and koji starter culture (Aspergillus oryzae) nutrient components, has an effective good effects on human body.

● Nutrients in miso
・Protein ・Vitamin B2 ・Vitamin B12 ・Vitamin E ・Enzyme ・Saponin ・Trypsin inhibitor ・Isoflavone ・Lecithin ・Choline ・Prostaglandin E ・Brown pigment ・Dietary fiber


Miso's Health Effect #1 Diabetes Prevention Effect

It has been found that the brown pigment (melanoidin) of miso has a postprandial blood sugar reducing effect.
It seems that this effect is stronger as the miso's color is darker.

It has also been suggested that it may lower blood sugar levels by facilitating pancreatic function.

Reference: Deputy President of Kagawa Nutrition University / Gomyou Toshiharu
味噌の科学と食塩 ; Science and Salt Content of Miso (in Japanese)
Diabetes Prevention Effect

Miso's Health Effect #2 Suppression of Cholesterol Level

It is known that the component "Saponin" contained in soybean has an effect of prompting the lowering of blood cholesterol.

As the substance is still functioning even after the soybean is processed into miso, it can be said that miso has the effect of suppressing the level of coteresterol.

Reference: Deputy President of Kagawa Nutrition University / Gomyou Toshiharu
味噌の科学と食塩 ; Science and Salt Content of Miso (in Japanese)
Suppression of Cholesterol Level

Miso's Health Effect #3 Anti-aging Effect

Active oxygen is one of the causes of aging and disease.
Saponin has been reported to work to eliminate these kind of reactive oxygen and reduce the risk of diseases.

Reference: Deputy President of Kagawa Nutrition University / Gomyou Toshiharu
味噌の科学と食塩 ; Science and Salt Content of Miso (in Japanese)
Anti-aging Effect

Miso's Health Effect #4 Osteoporosis Prevention

Isoflavones, which are famous for their abundant nutritional components in soybeans, act on female hormones and are able to prevent osteoporosis, which is causing low bone-density.

Reference: Deputy President of Kagawa Nutrition University / Gomyou Toshiharu
味噌の科学と食塩 ; Science and Salt Content of Miso (in Japanese)
Osteoporosis Prevention

Miso's Health Effect #5 Cancer Prevention

Studies have shown that the antioxidant effect of miso is effective to prevent cancer and other diseases.

In particular, the effect on gastric cancer is remarkable, and it's said that it's also effective on gastric ulcers.

Reference: Deputy President of Kagawa Nutrition University / Gomyou Toshiharu
味噌の科学と食塩 ; Science and Salt Content of Miso (in Japanese)
Cancer Prevention

Traditional Producing Method of Miso

Miso is produced by boiling and crushing soybeans, then fermenteing them in a cool and dark place called "miso storehouse".

It seems that this method has hardly changed since Edo Period.

We will introduce you the traditional and deep, producing method of miso.

  • Simmering the Soybeans


    1. Simmering the Soybeans

    Simmer the soaked soybeans overnight in a large pot.
    It can also be done by steaming at high pressure with a pressure cooker.

  • Crushing the Soybeans


    2. Crushing the Soybeans

    Smash the boiled and softened soybeans with a machine.
    Crushing the soybeans will also give the effect of stimulating fermentation process.

  • Mixing the koji and salt


    3. Mixing the koji and salt

    Prepare the fermentation by mixing crushed soybeans, koji, and salt.

  • Preparing the Miso in Storehouse


    4. Preparing the Miso in Storehouse

    Prepare miso in the large wood barrels in miso storehouse.

  • Fermenting the Miso


    5. Fermenting the Miso

    Let the miso which prepared in barrels storehouse fermented.
    It's said that it's good to do the preparation of miso-making around January.

  • The Completion of Miso


    6. The Completion of Miso

    Miso is completed around October to November when the temperature is decreasing.

You Can Also Make Miso at Home!

You can make miso at home if it's in small amount.

It's pretty easy to make miso at home by preparing a storage container (can also be made of plastic) after mixing the ingredients of soybean, koji, and salt.

Let's try making miso at your home!

How to Make Miso

How to Make Miso
We will tell you about the recipe of how to make miso paste.
This recipe is an instruction from miso manufacturer summarized by Kawashimaya.
You can use this as a reference to make your own miso.
Please enjoy making miso to your heart's content. We hope that you can make delicious miso!

Read the article of "How to Make Miso" here.

We also sell Handmade Miso Set that will support the making of miso at home.

Please take a look here:
Handmade Miso Set

About the Expiration Date of miso

For usual miso available in market, the best-before date is about 6 months until it's expired.

Since it's a "best before" date, basically , you can eat it even after several days past the date.

However, depending on the storage conditions, the fermentation process happening inside miso may be continue to progress which will cause the miso to be spoiled.

For example:

  • ● When opened and stored at room temperature
  • ● Unopened but stored at normal temperature in summer


If you have opened the miso, be sure to put it in the refrigerator, and do not store at normal room temperature.
Especially during the hot summer season, you should put it in the refrigerator.

Miso is originally considered to be a seasoning that has much salt content and not easily be spoiled/rotten.

However, in humid seasons, mold may grow.

In addition, if it's placed in a high temperature, fermentation will continue to proceed and the flavor and taste of miso will be lost.

The best delicious time to eat miso is before the best-before date and it's important store it in the right place to enjoy the most delicious miso.

About the Expiration Date of miso

Q & A About Miso

Mold has grown on miso, but can I still eat it?
You can still eat the miso by removing the surface which has mold on it and a little bit of its surroundings.
In particular, blue mold may cause illnesses like stomachache, so be sure to take it.
Miso has discolored/change of color.
Fermentation is probably continue progress.
There is no problem with the quality, but it seems that the flavor has changed from the beginning.
The handmade miso that I made tasted sour.
It seems that lactic acid bacteria have been bred in the miso.
It's probably due to the lack of salt during preparation.
Unfortunately, it's not possible to remove the lactic acid bacteria that have once propagated.
You should make miso from the beginning again.

Recommended Miso Products

Here are the Kawashima the Japan Store's recommended products of miso!