The Ultimate Guide to Miso

Miso is one of the main seasoning ingredients used in Japanese cuisine. If you’re familiar with Japanese foods, then you’ve definitely come across Japanese miso-containing foods such as miso soup before. Why is miso so prominent in Japanese cuisine though? What even is miso? We’re going to cover both of these questions and a whole lot more, as we take a deep dive into the world of miso in this article. 

What is Miso?

Starting with the basics, miso is a seasoning paste essential to Japanese cuisine. It is a thick paste traditionally made by mixing soybeans with salt and koji - a fungus or mold used for fermentation. Miso has a complex flavor profile, and depending on a range of factors, it can be described as salty, umami, sweet, earthy, savory, and even as rich or intense. The key variables that affect the flavor of miso include the type of koji, amount of salt, duration of fermentation, temperature, and the fermenting vessel used. 

Miso paste can also consist of other ingredients such as rice or barley. Chickpeas, rice or adzuki beans are sometimes used in place of soybeans, so that those with soy allergies can also enjoy miso’s unique flavor. As a rule of thumb, however, traditional Japanese miso generally contains soybeans.

A Brief History of Miso

According to the Marukome corporation, one of Japan’s leading miso producers, miso was most likely first introduced to Japan via China during the 7th century.

During the Heian period (794-1185), miso was considered to be a luxury item used only among the elite, to the extent that it was apparently used as a gift or as a form of payment to those with elite status. Since it was a precious commodity, it was not used as an ingredient in soup as it is today, and was instead spread directly on food and eaten.

Miso soup first emerged during the Kamakura period (1185-1333) when Buddhist monks began using mortars that could easily grind grain to be dissolved in water. This soup became a staple for Kamakura samurai. Over time, as farmers began making their own homemade miso, common people began to incorporate miso into their diets as well. In those days, it seemed that everyone wanted to boast that their version of homemade miso was the best. 

In the Sengoku period, samurai took miso with them to the battlefield, since it could be preserved and carried around in its dried or grilled form. Miso became even more highly regarded then, as it was not only a convenient seasoning, but also a valuable source of protein for the samurai.

Miso culture truly flourished during Japan’s Edo period (1603-1867) and specialized miso shops began popping up in addition to restaurants using miso in their dishes. Miso paste eventually became so popular that it could be found in every Japanese home or kitchen.

What is Miso Used For

Other than being the key ingredient in miso soup, miso is a surprisingly versatile ingredient. It can be used as a seasoning, made into a sauce to complement grilled fish or vegetables, blended with walnuts to make a side dish, or even infused into beer!

In other countries, miso has also gained popularity and is even used to make desserts such as miso macaroons, or miso caramel tarts. Even though miso has traditionally been used for savory dishes, its infusion into desserts is brilliant, as the saltiness of miso complements sweet ingredients surprisingly well. The sky's the limit with miso.

Miso Soup 

Many Japanese people commonly consume miso soup on a daily basis. But what exactly is miso soup and how is it made? Miso is usually mixed with dashi soup stock, vegetables, and tofu cubes to make a soup. Sometimes noodles or meat are added to give it more flavor or texture. 

What does miso soup taste like?

Miso soup has a savory flavor with a hint of saltiness. The strength of the soup mainly depends on the amount of salt used in the miso paste and the type of miso used. Another factor that affects the taste is the amount of koji used. The higher the amount of koji, the sweeter the miso will taste.

What is in miso soup?  

A classic take on miso soup recipe includes miso, dashi stock, wakame seaweed, tofu, and green onion. However the sky’s the limit for this umami-packed nutritious soup. You can really add any ingredients you have in your fridge to miso soup, but some other common Japanese ingredients include: 

• Long green onion 
• Shiitake mushrooms 
• Carrots 
• Daikon radish 
• Thinly sliced pork belly 
• Clams 

If you’re looking for some miso soup inspiration, then be sure to check out our blog for authentic Japanese miso soup recipes. 

Is miso soup healthy?

There are several health benefits to consuming miso soup. Firstly, miso is good for gut health as it contains probiotics. Miso is also full of antioxidants and is said to reduce the risk of breast cancer, support brain health, and enhance the immune system.

If you are trying to lose weight, miso soup is low in calories, full of nutrients, and can therefore be consumed regularly as part of a well-balanced diet.

How to Make Miso

Making miso is not a quick process. It is in fact a labor of love. Soybeans and sometimes other grains, such as rice or barley, are first soaked. The soybeans are then boiled and steamed, while the other grains are simply steamed. The koji starter is then added, and the mixture is left to ferment for a few days. Salt and water are added next, before transferring the mixture to gigantic wooden casks.

Traditionally, in some factories, a worker with rubber boots will get into the cask and stomp on the miso. This process gets rid of any air that could have been trapped in the miso mix, which could potentially cause mold to grow. Since the miso mixture is so dense, the worker can stand on its surface without sinking into the paste. Stones are laid on top of the wooden lid that covers the cask, firmly pressing down on the mixture.

The fermentation process can last anywhere from a few months to even a few years. The longer the fermentation period, the more complex the flavor profile is said to be, and the darker the color. There are restaurants in Japan that make and ferment their own miso as well.

Types of Miso Paste

There are more than 1,300 types of miso in Japan, each with its own distinctive flavor profile. Miso paste can be differentiated according to its malt type, region, texture, taste or even color. Broadly speaking, miso can be categorized into three colors: red, white, and yellow. Here is a brief explanation of each color type and how it is used:

• Red miso – known as ‘aka miso’ in Japanese, red miso paste is fermented longer than white and yellow miso, giving it a more intense flavor. It is also made of a higher percentage of soybeans than the other kinds of miso. Red miso is often used to make miso soup, especially in Japanese restaurants.

• White miso – known as ‘shiro miso’ in Japanese, this kind of miso is fermented for the shortest amount of time out of all of the miso pastes. Usually, it is fermented for no longer than three months. If you are new to miso, then white miso is a good one to start with because it has a milder and sweeter flavor. 

• Yellow miso – known as ‘shinshu miso’ in Japanese, yellow miso ranges in color from yellow to light brown, and is fermented slightly longer than white miso, usually up to a year. It is slightly sweeter than red miso.

Varieties of Miso Paste

Other than by color, miso can also be classified according to the ingredients it is made of. The four main types of miso are rice miso, barley miso, and soy miso, as well as blended miso paste, which is a combination of the different types.

• Rice miso is made from rice, soybeans, and salt. It is made by adding rice koji to soybeans.

• Barley miso is made from barley, soybeans, and salt. It is made by adding barley koji to soybeans.

• Soy miso is made from only soybeans and salt. It is produced largely in Japan’s Chukyo Region. 

Rice miso (Kome Miso in Japanese) is the most popular type of miso in Japan. It is made by fermenting a mixture of soybeans and rice. The color is very light due to the color of rice and its  short fermentation time. That’s why it is referred to as Shiro Miso, or white miso. Rice Miso has a light taste and a mild sweetness.

Barley miso (Mugi Miso in Japanese) is a variation of white miso because of its relatively light color, even though it is much darker than Rice Miso. It is made of a mixture of soybeans and barley, and is especially popular in the Kyushu region.

Soy miso (Mame Miso in Japanese) has a dark reddish-brown color, and requires a long fermentation period. It originates from  the Edo period, and is now mostly produced and consumed in the Chukyo region. While not as sweet as other varieties, it has a strong, umami flavor, with a hint of acidity. Soy miso can be mixed with lighter miso varieties for a more complex flavor.

Is Miso Alive?

Miso is alive! It contains living bacteria cultures, so that it continues to ferment and its flavor continues to change with time. This living bacteria in unpasteurized miso makes it a probiotic food, which helps to build up healthy gut bacteria. In fact, it is recommended to keep these enzymes alive, by stirring miso into the soup after taking it off the heat, rather than boiling it in the soup. Most miso pastes sold in supermarkets, however, have been sterilized by heat, which stops the fermentation process. If you want to buy unpasteurized miso, look out for ‘Nama Miso’, which translates to “raw miso” in Japanese.

Is Miso Allergy-Friendly? 

Since the key ingredients in miso are soybeans and rice, miso paste can be gluten-free, as long as no wheat or barley has been added to it. Sometimes, even when the ingredients do not contain gluten, the equipment could be cross-contaminated, or the ingredients could be flavored with barley. Koji, the fermentation starter, could also contain barley, so there may be trace amounts in the final product.

If you have a soy allergy but want to try miso, you can try this miso paste which uses brown rice in place of soybeans. 

Is Miso Vegan Friendly? 

Most miso pastes are vegan-friendly as well, but some of them contain added fish-based dashi. Most miso soups in Japan often contain dashi using fish as well. For vegans or vegetarians, it is best to check with the restaurant first. When making miso soup at home though, it is easy to make a vegan version by using kombu dashi instead.

Where to Find Miso 

Aside from Japanese grocery stores, miso can be found in most Asian grocery stores, if not the normal grocery stores, and sometimes even in health food stores, thanks to its increasing popularity. Our site also has a range of miso products you can get here. If you don't know which miso paste to purchase, you can also learn more about miso paste in this post, where we recommend our favorite miso pastes. 

If you’re unsure about which miso paste to purchase, we have an article that you can check out here where we recommend our top 9 favorite miso pastes.

Other than in the form of a paste, you can also find instant sachets of miso soup, or freeze dried miso soup enclosed in a thin wafer layer that make a fancy gift set.

How to Store Miso Paste

To preserve the flavor, miso paste should be kept in the refrigerator or freezer. Once opened, miso paste should be kept tightly wrapped in plastic wrap to not only prevent it from oxidizing but also to keep it from drying out.