Traditional Miso

Mitoku’s range of miso, made with highest quality organic ingredients, represents the finest of this traditional and essential seasoning and health food. This thick, savory paste is integral to authentic Japanese cooking, thanks to its bold umami and great versatility. Its complexity and richness of flavor derive from the fermentation that is fundamental to traditional production. This is what sets our miso apart from mass produced, quick-fermented products.

The fermentation used in traditional miso making develops the aroma, flavor, and color of miso, and also imparts high nutritional value. Miso contains active enzymes which aid digestion and support immune system health. Unpasteurized miso is thought to contain more of these beneficial enzymes than pasteurized miso. Mitoku’s miso range is organic and free from GMO and chemical additives.

  • Organic Brown Rice Miso Red – Unpasteurised

    This full-bodied and wholesome miso contains a deliciously satisfying balance of flavors. Mitoku’s brown rice miso is made using rice with its bran intact, meaning it is packed with dietary fiber, minerals, vitamins, and essential fatty acids. In addition, the unpasteurized form of this miso is loaded with beneficial enzymes. This is a great all-purpose miso that works particularly well in soups.

    *This product is also available in pasteurized form.

  • Organic Brown Rice Miso White – Unpasteurised

    Mitoku Brown Rice Miso White is unpasteurized, made with organic brown rice koji. It is distinctively light in color but rich in taste with pronounced saltiness, and is slightly sweeter than the red variety. Switching from a dark to a light miso can transform the taste and impact of a dish.

    *This product is also available in pasteurized form.

  • Organic Barley Miso – Unpasteurised

    This miso, known traditionally as “rural miso”, is characterized by its hearty and warming flavor, and is a great choice for soups, stews, and sauces. It is also distinguished by its barley aroma, derived from barley koji. Each product in our barley miso range has its own distinct color and flavor.

    *This product is also available in pasteurized form.

  • Organic Hatcho Miso – Unpasteurised

    Naturally fermented for two summers and two winters in 200-year-old cedar vats under the pressure of three tons of river rocks, Hatcho miso is the richest and heartiest miso variety. It has a distinctive astringent flavor and deep color, is very rich in protein and has mellow sweetness on the palate. Named “Hatcho” after the region in which it was first produced, it is now made under the direction of the family firm’s 19th successive president to a recipe unchanged since 1645.

  • Organic Sweet White Miso

    This light and sweet Kyoto-style miso is made in small batches, with a high ratio of rice koji to soybeans and a short fermentation process. Creamy and versatile, it has a distinctive white color and a low salt content. It is ideal as a dairy substitute and works well in dips, creamy sauces, desserts, and even baking.

What is Koji?

Koji is a fermentation starter made with the culture Aspergillus oryzae. The koji formation stage is the most crucial in the miso and shoyu production process. This is because koji is very rich in enzymes, which break down the raw ingredients and drive the critical fermentation process.

Koji is a key ingredient in many quintessentially Japanese seasonings and ingredients. The fungus from which it is derived, Aspergillus oryzae, is nature’s chef, imparting fermented foods with their distinct taste, complexity, and aroma, as well as heightening their benefits.

However this powerful yet delicate culture needs optimal conditions to thrive. This requires careful supervision. Experienced brewers must monitor temperature and humidity carefully throughout each stage of the koji-making process, to ensure that the taste and quality of the finished product is as good as it can be.


Salt and Miso

Salt is a vital part of the fermentation process. Its addition to the miso mixture halts the propagation of the Aspergillus oryzae, while simultaneously creating an environment that allows healthy, probiotic bacteria to thrive, kick-starting the decomposition process while keeping harmful bacteria at bay.



Miso is made by mixing koji, mashed soybeans, salt, and water, then leaving the mixture to ferment and mature. Different types of miso can be made by adding different types of koji to the mixture. Brown rice koji is used to make brown rice miso, and barley koji and soybean koji are used to make barley miso and soybean miso respectively. There are many variables that go into shaping the taste of miso, ranging from the area of production, its climate, environment, and traditions, to the approach and specific ingredients selected by an individual producer. Here we introduce the basic method of miso production.

Preparation and koji-making:

As with sake and shoyu, the most critical element in miso-making is the fermentation starter, known as koji. This kick-starts the all-important fermentation process. The quality of the starter does much to determine the quality of the finished miso. It is not enough to simply sprinkle rice, barley, or soybeans with koji spores. Instead, the koji needs to be provided with an effective medium to grow on. If soybeans are used, for example, they must be washed, soaked, and steamed to create the optimal conditions for the koji to thrive. The producers also need to be attuned to environmental conditions such as temperature and humidity in order to judge the correct ratio of koji to soybeans. These factors have a complex interrelationship, which can change with each batch.

Once the soybeans have been washed, soaked and steamed or boiled, they are mashed before being mixed with the koji.

The following photos illustrate the koji-making process for barley koji. Koji spores (Aspergillus oryzae) are sprinkled on steamed barley in a warm incubation chamber. Inside the chamber, the steamed barley is transformed into koji and becomes ready for miso making.

Fermentation and maturation:

The koji is now mixed with cooked soybeans, salt, and water in large fermentation vats. While most miso makers use metal vats, some traditional producers use wood, which provides the perfect environment for microorganisms to propagate and for the enzymes in the koji to get to work on breaking down the soybeans. The mixture is then left to ferment and mature. For the first 20~30 days, the mixture is churned to give a boost to the good bacteria in the mixture, which supplement the activity of the enzymes, and ensure that the mixture ferments evenly. After fermentation, the maturation period can be anywhere between three months and three years, depending on the miso variety.


From sweet, creamy, and light to hearty, robust, and dark, Mitoku has an wide range of miso varieties available to stimulate and enhance your cooking.

The key to fine miso cookery is not to overpower dishes with a strong miso taste, but to integrate the more subtle aspects of miso color and flavor in a gentle balance with other ingredients. For example, when making miso soup, the use of a kombu, shiitake, kombu-bonito, or vegetable stock helps achieve a full, rich flavor with considerably less miso than you would need if you boil vegetables in plain water and rely on miso to supply all the flavor. The latter method usually results in either an overly salty soup or one that is watery, bland, and unappetizing.

With respect to color, bright summer vegetables, such as sweet corn or yellow squash, and lightly cooked greens floating in the beautiful yellow to beige broth of a light miso soup are appealing in warm weather, whereas the earthy tones and hearty flavor of dark miso soup with chunky root vegetables and wakame or kale are pleasing during the colder months.

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