Skip to content

Miso 101: What is this Japanese Condiment in so many Recipes?

This is the ultimate extensive guide on how to buy and cook with delicious miso

Bookmark article to read later

By Epicurious US | October 27, 2023 | Recipes

In America, miso is often identified by its color, but labels of "red" or "white" do not even begin to cover the 1,300-plus types of miso found across Japan and the world.

For centuries, miso has claimed a central spot in the Japanese culinary canon. In recent years, the fermented staple has grown in popularity across the globe, dressing tangles of glossy spaghetti and adding nuanced flavor to baked goods. But what is miso exactly? And how can you incorporate it into your own cooking routine? Below, we’ll guide you through a few of the many, many varieties of miso available around the world and talk about a few of our favorite ways to use each one. But before we dive into all the kinds of miso you may spot at the supermarket, let’s start with the basics.

What is miso?

Miso, a.k.a. fermented soybean paste, is made by combining just three simple ingredients—soybeans, salt, and koji (a type of fungus cultivated on rice and other grains)—and allowing the mixture to age for months or even years. Factors like the type of koji used and the length of fermentation can result in infinite varieties of miso, including some that contain no soybeans at all (more on that below). In fact, over 1,300 variations of the umami-rich paste are in use today. It’s a vital ingredient in Japanese cooking, often used to bring a wallop of savory flavor to soups (like miso soup and hot pot), noodles, and yakitori dishes.

Miso has over 1,300 variations as an umami-rich paste widely in use today. It’s a vital ingredient in Japanese cooking. Image via Pexels.

An abbreviated history of miso:

Though miso has become emblematic of Japanese cuisine, the ingredient is believed to have originated in China or Korea. According to the Japan Miso Promotion Board, miso was first introduced in Japan in the 7th century. At first, miso was considered a delicacy, only available to Japanese nobility and monks—they ate the fermented paste either as a spread or on its own. In the 12th century, miso soup—which used a small amount of the precious paste to flavor dashi, a Japanese broth—became a dietary staple of Kamakura samurai. Today, rice and miso soup remain a popular Japanese breakfast.

Around this time, farmers began making their own miso, fueling its spike in popularity across Japan’s countryside. Using koji inoculated with grains grown on their land, Japanese homesteads created some of the signature regional types of miso that we have today. “Most sweeter miso and rice-based miso comes from the north of Japan, because that’s where the rice paddies are,” explains Bonnie Chung, founder of Miso Tasty and author of a cookbook by the same name. “Barley miso is really popular in the south of Japan because barley is more commonly grown there.”

The onset of the 17th century brought about the industrial production of miso, propelling the nutrient-dense soybean paste to widespread popularity. Still, class stratifications remained apparent in the trade and purchasing of miso. The emergence of a wealthy merchant class in major Japanese cities like Kyoto and Edo (now called Tokyo) led to an increase in demand for high-grade miso. “Traditionally, rice miso is more expensive than barley miso, because the grain is more expensive,” explains Chung. Accordingly, wealthier merchants could afford to purchase more expensive miso made with rice, whereas farmers and townsfolk often ate miso made with millet, barley, or other common grains.

How is miso made?

No matter what type of miso you’re dealing with, it all starts with a mold spore called Aspergillus oryzae, also known as koji. This ancient fungus appears in countless East Asian fermentation practices: It’s the “starter” used to ferment miso, soy sauce, sake, rice vinegar, and shōchū. In the case of miso, koji grows on the rice, barley, or another grain before it’s added to the soybean mash to start the fermentation process. “Koji’s protein enzymes break down the protein in the soybeans and create amino acids,” explains Mariko Grady, owner of San Francisco–based Aedan Fermented Foods. Over a period of months or sometimes even years, koji ferments the soybeans to yield a deep umami flavor.

The type of grain used to inoculate the koji is one key distinguisher between the types of miso. There is kome miso, made with rice koji; mugi miso, made with barley koji; and mame miso, made with soybean koji. Of these, kome miso—made with rice koji—remains the most widespread commercially produced miso.

The two most popular types of commercially produced miso are shiro (white) miso and aka (red) miso. Though these varieties may look very different, they’re made from the exact same ingredients: soybeans, koji, and salt. Image via Pexels.

Types of miso:

In America, miso is often identified by its color, but labels of “red” or “white” do not even begin to cover the 1,300-plus types of miso found across Japan and the world. “Especially around Japan, you can go to miso stores, which are a bit like a deli,” notes Chung, “and buy each type of miso by weight.”

The two most popular types of commercially produced miso are shiro (white) miso and aka (red) miso. Though these varieties may look very different, they’re made from the exact same ingredients: soybeans, koji, and salt. “The difference is the fermentation time,” Chung notes. The longer miso ferments, the deeper in umami flavor and darker in color. But other factors play a role here, too, such as the type of grain used and the ratio of soybeans to koji (the higher the percentage of koji, the sweeter the miso will be).

Shiro (white) miso is a sweet, mild miso with a white or yellow color. It gains its light, delicate flavor from a high proportion of rice koji to soybeans and a short fermentation (three months to one year). Pair white miso with chicken, roasted vegetables, or a white fish like cod; you can also use it in marinades, salad dressing, or miso butter.

Experts recommend seeking out miso made in Japan, given the country's rich miso-making tradition. Image via Pexels.

Aka (red) miso is a dark, rich miso made with a higher proportion of soybeans to rice koji. Aka miso ferments for a longer amount of time—typically six months to a year, but potentially up to five or 10 years—and ranges from reddish brown to nearly black in color. Its deep flavors can stand up to dark meat, hearty vegetables (use it in these mushroom burgers), oily fish like mackerel or salmon, and richer stews or braises like mabo don, a Japanese riff on mapo tofu.

One note: If you see a tub of red-hued miso at the grocery store, it hasn’t necessarily aged for longer than the paler stuff. Some high-volume producers quick-ferment their miso, shortening the process to a matter of weeks, and then expose it to oxygen to yield a darker color.

More misos to know:

Shiro (white) and aka (red) miso are the varieties you’re most likely to find at the grocery store, but there are over 1,300 different varieties of miso to know and love. Many of these types of miso are characteristic of certain regions in Japan—they’re often named after the prefecture where they originated. Here are a few more types of miso to familiarize yourself with.

Mugi miso contains fermented soybeans, barley koji, water, and salt. Because it uses barley instead of rice koji, mugi miso is not gluten-free. It can range from sweet, with a light yellow color, to full bodied, with a red hue.

Mame miso is made exclusively from soybeans, with steamed soybeans, soybean koji, water, and salt. This dark miso has an intense, pungent flavor and dark brown color.

Hatcho miso is a special type of mame miso made in Japan’s Aichi prefecture. “Hatcho miso is completely black, soy-sauce-colored, and it has the consistency of fudge,” describes Chung. This intense variety of miso, which is made from pure soybeans and soybean koji, ferments for two to three years. It’s named hatcho—eight (units of length) in Japanese—because this miso was made eight blocks from the Okazaki Castle. Much like Champagne must come from the region in France, “You can only call it hatcho miso if it comes from that particular faction,” Chung notes.

Shinshu miso is fermented for a slightly longer time than most shiro miso. Often called yellow miso, it can be identified by its golden yellow color and mild flavor.

Genmai miso is made with brown rice, not white rice. Known for its earthy flavor and golden brown color, it’s typically sweet and mild enough to eat raw. Use it in this Winter Stew.

Inaka miso is a rustic variety of homemade miso popular among farmers across Japan’s countryside. It can be made with rice or barley and is typically fermented for a longer period of time, giving it a dark brown color and robust flavor. You likely won’t find inaka miso available commercially in the United States.

10-year miso is a thick, charcoal-colored paste used to “cleanse the liver and jump-start digestion,” according to Shen Blossom, a company specializing in botanical extracts. “Some people love 10-year miso,” says Grady of the dark, hyper-potent stuff. It still has the miso taste, but “it’s kind of like medicine,” Grady notes.

Does miso go bad? How should you store it?

One of the many beauties of miso is that, like many other fermented foods, it never technically expires—however, there are a few caveats. While miso does not necessarily go bad, improper storage or cross-contamination can lead to oxidation and/or mold growing on your miso. If you buy miso at the store, Grady recommends storing it in the refrigerator to stop fermentation and prevent mold. When stored properly, miso can last for upward of a year in your fridge.

As you dip into the container over time, oxidation will cause the miso to darken in color. To protect against oxidation, press a piece of parchment paper or plastic wrap onto the surface of the miso.

How to shop for miso:

There are a few things to look for when shopping for miso. “There are ways to make cheap miso by accelerating the fermentation,” Chung explains. Some companies may include additives in their miso paste, such as sweeteners or alcohols, to speed up production, but these also may impact the miso’s shelf life. Generally, you’ll want to seek out brands that contain nothing more than soybeans, some type of grain, and water. These brands may also list koji, salt, or seaweed among their ingredients, all great additions. If possible, inspect the texture of the miso. “Cheaper types of miso are heavily milled; the paste is so smooth it’s almost sticky,” notes Chung. “Natural miso should have a bit of texture,” she advises, ”a bit of graininess about it.”

You can buy miso at most supermarkets, though Asian or Japanese specialty stores (or online Asian grocery purveyors) will likely have a wider selection. Image via Pexels.

You can buy miso at most supermarkets, though Asian or Japanese specialty stores (or online Asian grocery purveyors) will likely have a wider selection. Here are a few of our favorite miso brands to shop online.

Chung recommends seeking out miso made in Japan, given the country's rich miso-making tradition, but you can also find quality miso from companies in the US that have been experimenting with various miso-making techniques. South River Miso—one of our favorite domestic miso companies—uses short-grain brown rice for its koji, whereas Maryland-based White Rose Miso uses Carolina Gold rice from nearby Marsh Hen Mill in its white miso.

These new-wave miso producers have also devised unique types of miso, some of which are soy-free. White Rose Miso offers benne miso and farro miso. Aedan Fermented Foods produces both traditional white miso, fermented for 12-plus months, and soy-free chickpea miso. South River Miso is the only known producer of adzuki bean miso, but it’s the three-year barley miso that stole our hearts (use it in this barley miso-marinated chicken yakitori).

Want to make your own miso? You’re in luck: In addition to teaching monthly miso-making workshops, San Francisco’s Aedan Fermented Foods sells miso-making kits online. The kits come with organic soybeans, fresh organic koji, sea salt, and instructions; order one here.

How to cook with miso:

Ready to get cooking? The Epicurious recipe archives are full of ways to use that jar of miso. Go for more traditional Japanese dishes like miso-marinated salmon or miso soup (our miso soup recipe calls for white miso, but Chung recommends blending white and red miso pastes together to achieve simultaneous sweetness and depth of flavor) or branch out to taste how umami-rich miso boosts the flavor of everything it touches, including saucy, cheesy noodles, sticky-sweet vegetable stir-fries, and even floral, fruity miso ice cream. Coat your potatoes in red miso butter or swirl a batch of ramen noodles in miso broth. Elevate condiments with a tablespoon of miso (miso mayo, miso-tofu ranch, miso sesame vinaigrette…) or think outside the box with miso desserts, like Miso-Maple Walnuts to sprinkle over ice cream, nutty crumb cake, or even Chocolate Miso Bread Pudding. Heck, rub it on your Thanksgiving turkey! Or just amp up the flavor on an everyday vegan banana bread.