All About Miso

An Introduction To Miso

Miso is fermented soybean paste commonly used in Japanese cooking.

Miso is fermented soybean paste commonly used in Japanese cooking. It comes in a variety of shades from pale beige to dark chocolatey brown, whether salty and sweet or mild. It can also be a smooth consisttency for cooking, or for sauces and dips, chunky with soy bean particles, nuts, or other seasonings.

In the seventh century, a Buddhist monk travelling from China brought back to Japan a soybean paste called “jang”. This “jang” underwent a transformation through the years, becoming two products: Japanese style soy sauce and miso.

Unfortunately, in the west it is difficult to purchase some types of miso because of their short shelf life, such as naturally produced sweeter and paler types. Because miso is still fairly unpopular in the west, production is limited here. Much of our miso is mainly exported from Japan, so only certain varieties, like naturally produced saltier miso, withstand the long journey. (Of course there’s always miso with preservatives….)

Soybeans, whether with a grain or alone, are introduced to a fementation starter, called koji, after which a lengthy fermentation process follows. For each manufacturer of miso, the koji starter is unique, imparting a signature flavour to the final product. Like yeast, it can be natural and specific to the region, or manufactured.

There are three types of miso: rice miso (currently the most popular), barley miso, and pure soybean miso.

Rice Miso

These days, rice miso is consumed the most in Japan. There are several varieties of rice miso, whether in the form of a smooth paste or a little chunky.

Akamiso (red miso) is true to its name. This type of rice miso includes shades from red to dark brown. It generally involves a longer production process during which fermentation is naturally controlled. Some popular varieties are Sendai, Echigo, Sado, and Tsugaru.
Amakuchi akamiso is similar to akamiso, but it is sweeter. A popular variety is Gozen.
Edo miso is also an akamiso, but is much sweeter than the other types of akamiso. It was so sweet, as a matter of fact, that in times before sugar, edo miso was the sweetener for desserts.

Shinshu and Akita miso are light yellow, originating in what is now Nagano prefecture. Currently, it is produced in a short process for mass production.
Amakuchi Tanshoku miso is a pale coloured miso that has been produced in quick manner. Often, bleach and food colouring is added to achieve the desired colour. Oxidization and browning is eliminated to achieve the pale colour.
Kyoto Shiro miso (aka saikyo) is very pale and quite sweet. This is the best type of miso for traditional Japanese cusine as in kaiseki ryori.

Did you know that sweeter types of miso are preferred by urbanites, while saltier miso is popular amongst the inhabitants of more traditional farming and fishing areas?

Barley Miso

Barley miso tends to be saltier, darker, and aged longer. It is popular on the island of Kyushu and the southern prefectures of Hiroshima and Yamaguchi on the main island of Honshu. It was traditionally the preferred type in Saitama prefecture as well, near Tokyo, but its popularity has decreased recently (perhaps due to its urbanization).

There are two main sub categories under barley miso: Karakuchi Mugi miso, and Amakuchi mugi. The former is deep and rich, aged for at least one year. The latter is sweeter and requires a much shorter fermentation process.

    To make miso with rice or barley, the following steps occur.

First, the grain is soaked overnight then drained well to be cooked by steam or boiling water.
After cooling, the koji starter (spores of aspergillus oryzae) is added to the grain spread out on trays. This begins the first fermentation. In mass production, this takes place in a climate controlled room which is warm and humid, however, it can be done naturally in warmer months of the year.
After about two days in natural production, the grain becomes a solid mass covered in powdery mold. It is crumbled and then mashed together with cooked soybeans and their liquid (tonyu) and salt to begin the second fermentation. This mixture is packed tightly into a deep cedar vat and covered with a drop lid and heavy weight. This stage takes anywhere from half a year to three years in natural production, and a matter of days or weeks in commercial mass production.
After the second fermentation, the product is ready to be consumed.

Soybean Miso

Soybean miso follows the same steps as the production method for miso with a grain, though eliminates the inclusion of a grain. Historically, miso was made simply by cooking soybeans then wrapping and molding them into balls. These were hung in a warm and humid place to which an air borne koji starter was attracted, thus beginning the first fermentation process. Once covered in mold, the soybean ball was unwrapped, mixed with salt and water, and packed into vats or kegs for second fermentation. This method is quite lengthy, taking a minimum of 12 months to three years to achieve the final product, but in some rural communities, it is still practiced generation after generation.
This type of miso is common in the central area of Honshu, including Gifu, Aichi, and Mie prefectures.
The most famous of all soymean miso is Hatcho. Hatcho originates in Aichi prefecture, in the city of Okazaki. In fact, the mold used in fermentation is believed to have originated in this city, and is not aspergillus oryzae, but aspergillus hatcho. The fermented soybeans are mixed with salt and a small amount of water for the second lengthy fermentation process, resulting in a firm and dark chocolatey coloured miso. Of all the miso, this one is the highest in protein and amino acids.
Another type of soybean miso is Mame, or Ichinen Mame. This follows the same process as hatcho, but uses aspergillus oryzae instead. It is also less firm, since more water is added during fermentation.
The last type is Tamari. If you read the information on this site about soy sauce, you’ll know that tamari is also a type of soy sauce. Residue from the production of tamari soy sauce is made into miso.

Health Benefits

Unpasteurized miso has many properties beneficial to one’s health.
It is a great alternative to meat, as it is high in protein and B12.
Concentrations of amino acids help neutralize pollutants in the air.
Blood is alkalized giving a great energy boost, better than coffee!
Natural digestive enzymes like lactic acid producing bacteria such as lactobacillus and pediococcus help break down and digest complex proteins, carbohydrates and fats.

Unfortunately, pasteurizing reduces many of these properties but is necessary for packaging in the shape of air tight bags, to stop fermentation (which can continue to occur).