Maibijin, the King of Acidic Sake - Mikawa Shuzojo, Fukui

Maibijin, known among aficionados as the "deviant sake," is unforgettable once tasted, captivating enthusiasts with its unique flavor. But how is Maibijin, with its distinctive strong acidity, crafted? In this article, we delve into the secrets of its taste through a brewery tour report and an interview with the brewer Mikawa Shuzojo and its master brewer, Kinya Mikawa.

Sake made with local rice from in-house field

The author visited the Mikawa Brewery in mid-September 2019. Nestled within a serene landscape, the brewery stands amidst rice fields where golden rice ears sway gently in the wind. Right in front of the brewery is its own rice field, where about 30% of the rice used in production—primarily the Yamadanishiki and Gohyakumangoku varieties—is cultivated, with all rice sourced from Fukui Prefecture.

Mikawa Shuzojo’s heritage traces back to 1887, with Mr. Kinya Mikawa, the sixth-generation owner, also serving as its head brewer. Despite suffering extensive damage during the Fukui earthquake in 1948, the brewery was resiliently rebuilt the following year, continuing its legacy of craftsmanship and dedication.

Just inside the entrance to Mikawa Shuzojo, the kama-ba (rice steaming area) greets visitors with a traditional atmosphere. Here, they employ a large, classic-style rice steamer, following the traditional method of placing a koshiki (steaming basket) atop a burner used to boil water.

A slightly cool ambiance fills the brewery, accompanied by the gentle sound of water flowing. This water, an essential element in the brewing process, is drawn from the Asuwa River’s groundwater nearby. Known for its soft quality and balanced mineral content, the water is pumped from a depth of 80 meters, maintaining a stable temperature of around 15 degrees Celsius, even during summer.

Upon tasting, the water has a smooth, delicate texture. “If you brew coffee with this water, it turns out delicious,” remarks Mikawa. It’s no wonder some visitors fill PET bottles to take home this prized water.

Pressed with a 100-year-old tool

A key element in the brewing process at Mikawa Shuzojo is the use of kifune, a traditional wooden press. These large, sturdy kifune have been meticulously polished to a high sheen, reflecting the careful attention and respect given to these essential tools.

At Mikawa Shuzojo, the traditional kifune pressing process is central to their brewing method. After fermentation, the sake is packed into pressing bags, and pressure is applied from above in three stages. First is the arabashiri, where sake is extracted by its own weight. This is followed by nakagumi, a gradual middle pressing, and finally seme, which applies firm pressure to draw out the remaining liquid.

Between these stages, several meticulous tasks are required. Before nakagumi, the pressing bags are repositioned to ensure even pressure across the kifune, and before seme, all bags are rearranged to the center, where pressure is strongest. These adjustments are labor-intensive, contributing to a process that takes approximately three days to complete, in stark contrast to the accordion-like Yabuta automatic press, which takes only half a day.

Unlike some breweries that line their kifune with stainless steel, Mikawa Shuzojo uses bamboo, preserving the tradition of hand-coating the wood with persimmon tannin to enhance its durability. The dedication to these time-consuming, careful practices underscores Mikawa Shuzojo’s commitment to craftsmanship and tradition.

Yeast starter that produces a rich acidity and umami

The creation of the yeast starter (shubo) is a crucial step in producing the intense acidity that defines Maibijin. Approximately half of the production employs the traditional Yamahai method, which relies solely on naturally occurring yeast within the brewery rather than adding cultivated yeast. This method requires considerable patience, taking around 50 to 60 days to develop the yeast starter fully.

In comparison, conventional quick-brewing methods using added yeast typically require about 14 days, while even the Yamahai method usually takes about a month. By dedicating twice the standard time to this process, Mikawa Shuzojo ensures that Maibijin’s distinctive flavor profile is meticulously cultivated from the very beginning.

Mikawa explains, “The yeast used in the traditional Yamahai method is relatively delicate. It requires frequent daki-ire warming (*1) and extended karashi resting periods (*2). The moromi (main fermentation) stage alone takes between 25 and 35 days, yet the time invested in developing the yeast starter far exceeds this.”

However, time alone doesn’t guarantee the ideal yeast starter. “Achieving the right balance between acidity and sweetness is essential,” Mikawa adds. Another critical aspect is nurturing the yeast to strengthen its natural fermentation power. “We avoid over-protecting the yeast, allowing it to develop resilience and fermentation strength naturally—much like raising a child.”

This patient, attentive approach to yeast cultivation reflects Mikawa Shuzojo’s philosophy. Respecting the unique characteristics of their yeast, they trust the process, allowing the yeast to reach its full potential. This careful waiting period, though time-intensive, is fundamental to achieving Maibijin’s distinctive profile.

(*1) daki-ire: Raising the temperature of the yeast starter by adding a barrel of hot water (warm water barrel)

(*2) karashi: The final stage of making yeast starter, during which the temperature is lowered before the starter is used in the moromi. Usually 5 to 7 days.

Encounter with Furosen led to the use of the Yamahai method

Mikawa Shuzojo began producing additive-free yeast starters a decade ago, inspired by their encounter with Uehara Shuzo’s Furosen from Shiga Prefecture.

Mikawa recalls, “About 12 years ago, I had a warmed glass of Furosen’s Yamahai Junmai. It had a pronounced sourness, a unique aroma, and a subtle sweetness reminiscent of warm umeshu (plum wine). At first, I thought Furosen wasn’t to my taste, but curiosity led me to try it warmed. The moment I took a sip, I was struck by its depth and complexity—it was delicious, bold, and memorable, the kind of sake you want to keep revisiting.”

This experience sparked his interest in the Yamahai brewing method, motivating him to create sake with similar richness and character at Mikawa Shuzojo.

In their first year, Mikawa Shuzojo used a kyokai yeast rather than relying on natural yeast. While this approach produced a sake with robust acidity and a pleasantly mellow flavor, it didn’t fully satisfy his vision. Driven by a desire to capture the brewery’s unique character, he began crafting Yamahai using their own natural yeast the following year, aiming to bring out the distinctive flavors of Mikawa Shuzojo.

Mikawa recalls, “That year, the sake’s distinctive sourness was particularly pronounced, and I worried about releasing such an intensely sour product. When the Prefectural Food Research Institute analyzed it, I was relieved to learn the acidity was not due to spoilage but rather derived from lactic acid-producing brewery yeast (*3). Even so, I was anxious about how customers would respond.”

To Mikawa’s surprise, the Tokyo market embraced this bold flavor. Feedback included comments like, “This sake is really intriguing!”, “The sourness is addictive,” and “It pairs well with meat dishes.”

The yeast-free sake sold out within the year, with its bold acidity becoming the signature trait of Maibijin.

(*3) The brewery yeast used at the Mikawa Shuzojo is said to produce more lactic acid than other yeasts in an environment without added lactic acid or yeast. Mikawa calls this yeast, which achieves a high acidity, “sanQ yeast”.

Delicious sake with a high acidity level

The Maibijin Yamahai Junmai sanQ stands out for its intense sourness. To put it into perspective, the acidity measured 4.0 last year, rising to 6.2 this year (as of 2020), with the highest-acidity variant, “Gaiden,” reaching an impressive 7.4. Given that standard sake typically has an acidity level around 1-2, these figures highlight the unique and bold profile of Maibijin.

While Maibijin’s strong acidity is striking, fans agree that its appeal goes beyond this initial impact. Alongside the acidity is a deep umami, a gentle sweetness, and a body that truly shines when warmed, bringing out a rich complexity. This layered profile makes Maibijin remarkably versatile, pairing well with a variety of cuisines—from Japanese and Chinese to Western and even more eclectic dishes.

Mikawa notes, “It’s not just about having high acidity; it’s about crafting a sake that’s genuinely delicious with that acidity. I hope people will appreciate the wonders of the brewing and fermentation processes rather than focusing solely on the ‘high acidity’ label.”

For Mikawa, brewing is not about creating a sake with mere impact but rather about capturing the unique qualities of the brewery, deeply rooted in the local environment.

“Sake breweries owe their existence to the local natural environment,” he explains. “The rice, the water, the changing seasons, and the natural yeast that thrives within the brewery. By honoring and utilizing these natural gifts, we create truly local sake.”

Passing on the joy of sake brewing to the next generation

Mikawa exclaims with a smile, “Sake brewing is fun.” His customers, fans of Maibijin’s bold acidity, return year after year in search of that signature sour profile. “It’s incredibly rewarding as a brewmaster to create this for them,” he says, clearly energized by their enthusiasm.

He’s eager to pass this joy to the next generation.

“Training successors isn’t difficult,” Mikawa shares. “I want people to work with me during the brewing season and experience the excitement of creating something with their own hands. I believe that any involvement in sake brewing will be valuable in the future because sake itself tells the story of Japanese culture.”

Mikawa sees sake as having the broadest flavor range of any alcohol in the world. “I enjoy sake with character—a rich, full-bodied flavor with tangy acidity that pairs beautifully with diverse cuisines. Drinking sake with a strong personality is fun, and making it is just as enjoyable!”

Mikawa Shuzojo grows pesticide-free sake rice in its own fields, while also designing innovative labels and bottles for the international market. With their endless ideas, the sake from Mikawa Shuzojo is packed with character, and we can’t wait to see what they create next.

Brewery Profile

Mikawa Shuzojo
Address: 36-15 Koinazuchō, Fukui (City), Fukui (Prefecture), 918-8131 Japan
Phone number: +81-776-41-1002
Founded year: 1887
Representative: Kinya Mikawa
HP: https://www.maibijin.com/