What is Miso? Ultimate Guide to Fermented Japanese Soybeans

With a 1,300-year-old history, miso is undoubtedly a staple in Japanese cuisine. Similar to other fermented foods like natto or sake, miso paste adds a ton of flavor to miso soup, salad dressings, marinades and more.

Today, we’ll be breaking down what miso is, its history and where to make it yourself during your time in Japan. Keep reading to learn all you need to know about fermented Japanese soybeans!

Miso is a paste made of fermented soybeans and koji, another fermented ingredient that’s made from rice, barley or soybeans. What differentiates one miso paste from another is the type of miso and the koji, which most miso makers would make themselves.

The process of making miso can take up to a year from start to finish. First, the soybeans are soaked in water for a day and a half. Then, they are steamed and mashed. Once the mash has cooled down, it’s mixed with koji, salt and the water the beans were soaked in.

At this point, the miso will be formed into a ball with a dough-like consistency. 

For the fermenting stage, the miso is sealed in an air-tight fermenting container, with one final spray of liquor to prevent mold from growing.

The miso paste is then left to ferment out of direct light for three months in the summer (due to higher temperatures speeding up the fermenting process), or six months to one year during the winter.

Originally brought over by Buddhist priests from China during the Nara Period, the process of miso-making was easily picked up by the Japanese people at that time, who already used fermentation and pickling techniques to preserve their food.

Because it contained rice (in the koji), miso was a delicacy reserved for the nobility until the Samurai caught wind of its “energy-giving properties.” 

Even as miso consumption trickled down to the common folk, different kinds of miso carried class implications. Lighter miso made from expensive white rice was considered the most luxurious, while darker miso made from more accessible grains such as millet or barley earned the nickname of “poor man’s barley.”

Since the 14th century, miso has become a beloved, staple ingredient for households across Japan, though what type is preferred depends on the region and personal preferences!

Despite its high levels of sodium, miso has many health benefits*:

As a result of its fermentation process, miso has a high level of good bacteria and reduced antinutrients, helping you to maintain a healthy gut flora. This helps to improve digestion, in addition to reducing gas, constipation, diarrhea and bloating.

Although multiple studies have shown that high-salt diets may increase the risk of stomach cancer, miso has been linked to a reduction of this risk. It is believed that the benefits of soy may be counteracting the negative effects of a high-salt diet.

By improving your gut flora, miso is said to boost your immune system by reducing the growth of harmful bacteria. This equates to a reduced risk of getting sick, and a quicker recovery from infections, should you get sick.

Source*

There are three different types of miso: white miso (shiro miso), red miso (aka miso) and mixed miso (awase miso). Let’s break down the differences between the three and when you should use them.

If you’re new to miso, white miso is an excellent entry point to the world of soybean paste thanks to its mild, slightly sweet flavor. 

You’ll typically see ramen being made with white miso to give it a creamy, light taste. Many desserts containing miso also tend to suggest using white miso, as it is akin to the nutty tahini paste, both in taste and texture.

Find out more: 5 Best Sapporo Ramen Restaurants for Miso Ramen

Red miso, sometimes referred to as “dark miso,” has a more pungent flavor due to a higher concentration of grains in the koji and a longer fermentation time than white miso. 

It’s salty, umami and nutty, making it a great addition to stews, braises and glazes. 

A common dish featuring red miso is miso dengaku, which is konyaku (yam cake) covered with a sauce of red miso, soy sauce, and sugar mixed together. Commonly eaten in the summer, miso dengaku is a good introduction to using red miso in your everyday cooking.

Find out more: 5 Must-Try Red Miso Dishes of Nagoya

As the name implies, mixed miso is made from a mix of red and white miso. The best of both worlds, mixed miso balances the umami flavor of red miso with the delicate sweetness of white miso. 

You can find instant miso soup made from mixed miso in supermarkets across Japan.

Now that you know the different types of miso, why not try making it yourself? Check out these miso-making experiences in major cities across Japan: 

For a hands-on workshop in central Tokyo, look no further than this Tokyo miso-making workshop. 

Taking place at the cozy cafe Amazake Cafe Kome Dreaming, you’ll do a miso tasting, make up to 700g of miso to take home as a souvenir, and enjoy miso soup made with your own hands!

If you’re looking for a longer experience, this Kyoto miso-tasting tour is perfect for you. Start the evening off at Sawai Soy Sauce Brewery for a soy sauce tasting. 

Then, head to Honda Miso Honten, a top-shelf miso brewery that has even supplied the Imperial Palace in the past. Next, a visit to Kotaro Vinegar Shop, where you’ll make your own ponzu sauce to take home with you. 

Cap off the night at The Corner Bar with three signature cocktails made from the ingredients you learned about on your tour.

Those seeking an intimate, laidback experience in a Japanese home will love this miso-making workshop in Osaka with certified guide and interpreter, Yoko. 

Learn about the regional variations of miso as you do a tasting of the three different types, after which you’ll make a 500g sample to take home as a souvenir. 

Enjoy a light lunch and fun conversation before departing.

In this miso-making class in Yokohama — only an hour away from Tokyo — you’ll mix, mash and taste a variety of different miso pastes and miso-based dishes. 

Allow your bilingual host to reveal the historical significance and fermentation methods of miso, enjoy a homemade lunch (with a healthy dose of miso included) and even get to take up to 1kg of the miso paste home with you!

If you find yourself down south in Kagoshima, step into the Sakura Kaneyo Soy Sauce Factory for a quick-fire Kagoshima miso-making experience that’s great for kids and adults alike. 

Enjoy a short tour of the factory before making your own Kagoshima-style miso (called mugi-miso) from scratch — taking up to 2kg home with you to taste after the fermentation process is done!

Looking for more information on Japanese soybeans? Check out these blog posts on different types of Japanese soybeans and a controversial ingredient: natto.

Store-bought miso will come in a plastic container with a tightly sealed top, so you don’t need to worry about keeping it fresh — though do be sure to check the expiration or best-by date as store-bought miso doesn’t last too long. 

For homemade miso, continue storing in an airtight container. 

Because miso doesn’t freeze completely, you can also store miso in the freezer to extend its shelf life, leaving it out to thaw for a few minutes before using so you can scoop it easily.

Miso can be used in a variety of dishes, miso soup being among the most popular. Add it to stews, salad dressings or even desserts for a unique, rich flavor.