Koshu Beer

Do you know Koshu Beer? It's a brewery in Katsunuma that focuses on making "sour beer."

It was founded in 2022 by Osamu Chizuwa. He used to work at a winery in Tokyo, and he fell in love with Belgian lambic, a sour beer fermented with wild yeast. He dreamed of making it in Japan.

Exactly, it's extremely niche. They combine cultivated wild yeast with lactic acid fermentation, then use bottle conditioning to create natural carbonation. Their main labels are three types: Muscat Bailey A Sour, Koshu Sour, and Plum Sour, all made with fruit from the Kyoho region.

The brewery itself is interesting too. Chizuwa personally renovated an old, single-story former sewing factory almost by himself. He handled the walls, doors, plumbing, and electricity all on his own.

What's more, he lives in Saitama and commutes by train for two and a half hours each way every day to brew. About 90% of their production is sold directly at beer festivals and other events.