Marusho Vinegar Brewery is a historic vinegar brewery in Nachikatsuura, Wakayama Prefecture. Founded in 1879, the brewery has preserved its traditional vinegar-making methods for more than 140 years.
Surrounded by the rich natural environment and spiritual heritage of Kumano, Marusho Vinegar Brewery produces vinegar using spring water from the Nachi Mountains and traditional Kumano cedar wooden barrels.
Nachikatsuura is best known for destinations such as the Kumano Kodo pilgrimage routes and Nachi Falls, but the region is also home to traditional industries that have developed from its abundant natural resources. Marusho Vinegar Brewery is an important example of this local heritage, preserving both the natural environment and the craftsmanship of Kumano.
One of the most important ingredients in Marusho’s vinegar is the underground spring water that flows from the Nachi Mountains.
This water is said to come from the same source as the famous waters of Nachi Falls, which are revered as the sacred waterfall and object of worship at Hiro-jinja Shrine, the auxiliary shrine of Kumano Nachi Taisha Grand Shrine.
With a hardness of only about 22 mg/L, the water is exceptionally soft. Its temperature remains around 16°C throughout the year, providing a stable environment for brewing.
The soft water helps create vinegar with a clean, gentle mouthfeel while bringing out its natural aroma, umami, and mellow character.
A well on the brewery grounds has been used since the company’s early days. The water is said to have continued flowing since the Edo period without ever running dry. The brewers lovingly call it “the water of life” and treat this precious natural resource with gratitude every day.
One of the most distinctive features of Marusho Vinegar Brewery is its continued use of large wooden barrels made from Kumano cedar.
The brewing facility contains enormous wooden barrels measuring more than 2 meters in both diameter and height. Many of these barrels have been carefully repaired and maintained over the years rather than being replaced.
Kumano cedar has a fine grain and is naturally resistant to leaking. Wooden barrels also “breathe,” creating an environment in which microorganisms important to fermentation can thrive.
Yeast and acetic acid bacteria that have lived in the brewery for generations contribute to the distinctive character of Marusho vinegar. In this sense, the flavor is shaped not only by the ingredients but also by the living environment of the brewery itself.
After World War II, many vinegar producers shifted toward mass production using enamel and plastic tanks. Marusho, however, compared vinegar made in traditional wooden barrels with vinegar made in modern tanks.
The brewery found that the wooden barrels produced superior aroma, umami, and depth of flavor. This experience reinforced the company’s belief that traditional wooden barrels are essential for producing truly flavorful vinegar.
That philosophy continues to guide the brewery today.
The traditional brewing method preserved at Marusho Vinegar Brewery makes extensive use of natural fermentation.
The brewery uses low-pesticide rice grown in the Kumano region. The rice is steamed and then combined with koji and the brewery’s natural spring water before fermentation begins.
Rather than attempting to completely control the microorganisms artificially, the brewers rely on naturally occurring yeast and acetic acid bacteria that live in the wooden barrels and the brewery environment.
Because fermentation changes according to the season, air temperature, water temperature, and condition of the microorganisms, the brewers must carefully monitor each batch based on generations of accumulated experience.
Even during winter, the temperature inside a fermenting barrel can remain around 40°C. The barrels are wrapped with traditional komo straw mats to help regulate their temperature.
Depending on the season, fermentation takes approximately 45 days in winter and 70 days in summer. After fermentation, the vinegar is aged for another four to five months or longer, allowing its acidity to soften and its umami and depth to develop.
The aging period varies depending on the product. Some varieties are aged for more than 500 days. This willingness to invest enormous amounts of time and effort is one of the foundations of Marusho’s distinctive quality.
The process begins by carefully steaming the rice used as the raw material. Traditional steaming equipment called a koshiki is used, and the amount of water absorbed by the rice and the steaming time are closely controlled.
This is one of the most important stages because the condition of the steamed rice has a major influence on the subsequent fermentation.
The steamed rice is combined with seed vinegar and spring water and mixed carefully inside the enormous wooden barrels using a traditional paddle called a kai.
Two important fermentation processes then take place. Natural yeast converts sugars into alcohol, after which acetic acid bacteria convert the alcohol into acetic acid. Gradually, the mixture develops into vinegar.
Once fermentation is complete, the vinegar is aged for an extended period.
During aging, the sharpness of the acidity gradually becomes more mellow, while deeper flavors and richer aromas develop. Because the process follows the natural rhythm of the microorganisms and the changing seasons, each barrel is carefully monitored by experienced brewers.
After sufficient aging, the vinegar undergoes heat treatment and is carefully bottled.
Each product is then inspected to ensure that it meets the brewery’s quality standards before being shipped. The combination of traditional craftsmanship and careful quality control helps maintain the distinctive character of Marusho vinegar.
The history of Marusho Vinegar Brewery has not always been easy.
During the difficult years following World War II, the brewery faced shortages of raw materials. Another challenge arose when wooden barrels that had not been used for a long period lost the microorganisms necessary for proper vinegar fermentation.
The brewers obtained microorganisms from other breweries and repeatedly prepared new batches until the desired bacteria successfully became established in their own wooden barrels.
Thanks to their persistence, the tradition of wooden-barrel vinegar brewing survived without interruption.
The brewery also continued to prioritize quality when the Japanese food industry increasingly embraced mechanization and mass production. Rather than choosing efficiency above all else, Marusho chose to protect the authentic flavor created by its traditional methods.
In doing so, the brewery has continued to develop alongside the natural environment and cultural traditions of Kumano.
One of Marusho Vinegar Brewery’s best-known products is Nachi Kuro Komezu, a special black vinegar made exclusively from glutinous brown rice.
It is produced using spring water from the Nachi Mountains and traditional Kumano cedar barrels, then aged for approximately 500 days.
The product was developed after Michio Kushi, an internationally known authority on macrobiotic philosophy and cuisine, asked the brewery to create vinegar using glutinous rice.
At the time, glutinous brown rice was considered difficult to use for vinegar production. After considerable experimentation, Marusho succeeded in developing a distinctive black vinegar that remains unusual even by international standards.
Its quality has received international recognition, including the Monde Selection Grand Gold Medal for 13 consecutive years beginning in 2007.
Today, the product is exported to destinations around the world, including European countries such as France and Italy, as well as the United States, China, Taiwan, Singapore, and Australia.
When visiting Nachikatsuura, it is worth looking beyond famous attractions such as the Kumano Kodo and Nachi Falls to discover the traditional industries rooted in the region.
Marusho Vinegar Brewery represents the meeting point of Kumano’s natural environment, history, local knowledge, and generations of craftsmanship.
The spring water of the Nachi Mountains, Kumano cedar wooden barrels, microorganisms that continue to live inside the brewery, and the skill and dedication of its brewers all contribute to the finished vinegar.
The result is more than simply a seasoning. Each bottle represents the natural environment and traditional culture of Kumano.
For more than a century, Marusho Vinegar Brewery has remained committed to preserving its traditional methods while maintaining the quality of its products.
For travelers exploring Nachikatsuura, discovering this unique world of traditional vinegar brewing offers a different way to experience the character of Kumano—through its water, forests, craftsmanship, and flavors.