Kayashima Sake Brewery Former Koji Room

What the Kayashima Sake Brewery Former Koji Room is

The Kayashima Sake Brewery Former Koji Room (萱島酒造旧麹室, Kayashima Shuzō Kyū-kōjishitsu) is a single-storey timber building from 1915 at Kayashima Sake Brewery in Tsunai, Kunisaki City, Oita Prefecture, and was registered as a Registered Tangible Cultural Property on January 16, 1998. It has a tiled roof and a building area of 40 m².

As the name says, the Kayashima Former Koji Room was once the brewery's Kojimuro, the room where koji was grown. According to the official description it now serves as long-term storage for ginjō sake.

Where the koji was made

Koji is steamed rice inoculated with a mold, Aspergillus oryzae, that turns starch into sugar. The brewery's own account says its koji takes two days to make and is handled in trays and on a bed at different stages; the finished koji goes into the yeast starter and the mash. The mold needs warmth and humidity, which made the koji room the most closely controlled space in any brewery.

The Former Koji Room is 4 by 3 ken; taking 1 ken as about 1.8 meters, that is roughly 7.3 by 5.5 meters. It stands just south of the Former Muromae, with its ridge parallel to the long Nakagura. The Former Muromae next door, the official description says, was where koji was cooled after leaving the warm room. Side by side, the two buildings trace the koji process across the ground.

Board walls and a small vent in the south gable

The Kayashima Sake Brewery Former Koji Room is clad in boards on all sides. The detail to find is a small window high in the south gable, which the official description calls a vent and singles out as the building's design accent.

A vent of this kind lets out trapped heat and moisture. In a room where temperature and humidity had to be managed, the opening high in the gable was very likely a working control, and on an otherwise plain board wall it also gives the building its face.

It was registered for contributing to the historic landscape of the country. Kayashima Sake Brewery is also the brewery that began selling competition-grade ginjō in 1963 under the name Hizōshu, and today it is the old koji room where ginjō is laid down.

Seeing the Kayashima Sake Brewery Former Koji Room

The Kayashima Sake Brewery Former Koji Room stands toward the south of the site, south of the Former Muromae, and is in use for storing ginjō, so the interior is closed. Ask at SAKE GALLERY Tohzai or call the brewery (+81-978-72-1181) about viewing the exterior.

If you get the chance, stand in front of the south gable and look up: one small vent above the board wall tells you most of what the building was for.