A Traditional Japanese Miso Brewery – Maruman Jozo

Miso is one of Japan’s most treasured traditional fermented foods.
For centuries, it has been an essential part of Japanese cuisine, adding rich flavor and depth to everyday meals.

Maruman Jozo is a traditional miso brewery in Japan that has been preserving the art of miso making for over 70 years.
Using carefully selected ingredients—soybeans, rice, salt, pure water, and koji—we craft authentic miso through the power of natural fermentation.

Miso making is not only about producing a seasoning.
It is about respecting the gifts of nature, the wisdom of fermentation, and the craftsmanship passed down through generations.
From our brewery in Japan, we continue to share the rich flavors and traditions of Japanese miso with people around the world.

The History of Miso

Miso is one of Japan’s most important traditional foods, but its history goes back much further than many people imagine.

The origin of miso is believed to have connections with ancient fermented foods from China, such as “jiang,” which were introduced to Japan and gradually developed into a unique Japanese seasoning.
Another theory suggests that miso evolved directly from fermented foods created in ancient Japan.

Over centuries, miso became deeply connected with Japanese daily life.
During the Kamakura period (1185–1333), the tradition of enjoying miso soup established itself, and during the Edo period (1603–1868), home-style miso culture spread throughout the country.

Today, miso is loved not only in Japan but around the world as “MISO”—a symbol of Japanese fermentation culture and a healthy food with a rich history.

The Power of Koji

In Japanese fermentation culture, koji is the invisible power that creates depth, flavor, and harmony. Koji is made by cultivating koji mold (*Aspergillus oryzae*) on steamed rice, grains, or soybeans.
Though simple in appearance, these tiny microorganisms play a remarkable role in transforming ordinary ingredients into rich fermented foods such as miso, soy sauce, sake, and amazake.

Koji produces various enzymes that break down proteins, starches, and fats. These natural processes create the rich umami, gentle sweetness, and complex aromas that define Japanese fermented foods.

Among these, rice koji (*kome koji*) has been especially treasured in Japan for centuries.
By growing koji mold on rice, the natural sweetness of the grain is enhanced while fermentation creates a variety of beneficial compounds.
This makes rice koji the foundation of many traditional Japanese foods.

At Maruman Jozo, we continue to value the power of koji passed down through generations.
By carefully nurturing rice koji and allowing fermentation to work naturally, we create miso with a deep flavor and gentle character.
Koji is more than just an ingredient—it is a symbol of Japanese wisdom, where human craftsmanship and natural microorganisms work together.

The Nutritional Power of Miso

Miso is not only a traditional Japanese seasoning, but also a nutrient-rich fermented food that has supported Japanese health for centuries. In Japan, there is an old saying: “Miso keeps the doctor away.
” This reflects the long-held belief that miso contributes to overall health and well-being.

Miso contains high-quality plant-based protein from soybeans, dietary fiber, vitamins, minerals, and essential amino acids. During the fermentation process, koji enzymes break down soybean proteins into amino acids, making the nutrients easier for the body to absorb.

Miso is also known for beneficial components such as isoflavones, lecithin, and antioxidants.
Furthermore, the microorganisms created through natural fermentation help support a healthy gut environment.

Another remarkable feature of miso is how its flavor and nutrition evolve over time.
Through careful fermentation and aging, simple ingredients transform into a food of exceptional umami and natural richness.

For the Japanese people, miso soup* has long been a simple yet essential daily nourishment—bringing warmth and the benefits of fermentation to every meal. Miso represents the true wisdom of Japanese culinary tradition: a delicious way to enjoy both heritage and health.

*Miso soup is a traditional Japanese soup made with fermented miso paste, dashi broth, and seasonal ingredients, representing Japan’s appreciation for natural flavors and wholesome nutrition.

Our Craftsmanship

Handcrafted Fresh Koji Made from Japanese Rice

Maruman Jozo’s fresh koji made from Japanese rice is carefully crafted by skilled artisans, drawing on nearly 80 years of experience in miso making.

With its strong fermentation power, it is ideal for making authentic amazake, shio koji, and delicious homemade miso at home.

>> Fresh Koji Made from Japanese Rice

 

A Message from Our Brewery

We hope this article gives you a deeper appreciation for the charm of miso—a treasured part of Japanese food culture passed down through generations.

The ingredients of miso are remarkably simple: soybeans, rice, salt, and koji.

Yet through the slow power of natural fermentation, the innate umami of each ingredient is fully brought out, transforming them into a rich and deeply satisfying flavor.

Miso is far more than just the base for miso soup. It is a versatile fermented seasoning that elevates soups, marinades for meat and fish, simmered dishes, and even fresh vegetable dips. It offers endless ways to enrich your daily cooking.

The rich nature of Fukushima, generations of craftsmanship, and the power of natural fermentation—all of these elements come together to create the unique flavor of Maruman Jozo.

We hope you enjoy the authentic taste of Maruman Jozo miso at your daily table, bringing a new richness and depth of flavor to your favorite dishes.

Shintaro Tokiwa　Maruman Jozo

Maruman Jozo’s “Furudono Naturally Brewed Miso” is made with 100% Japanese ingredients—locally sourced soybeans, rice, and salt. Because miso is made from simple ingredients with nothing wasted, the quality of each element directly shapes its flavor. Carefully selected ingredients, the living power of koji, and the blessings of nature create a rich, authentic taste. We are deeply grateful for the dedication of the local farmers, the skilled koji makers, and the rich natural environment that support our craft. At Maruman Jozo, we remain committed to bringing out the absolute best in these precious gifts. We hope you experience and enjoy the true taste of traditional Japanese fermentation.

Our Miso Collection