After 28 years of custom woodworking in Philadelphia and New York City, John Cox opened Quercus, a barrel and tank cooperage in New York’s Hudson Valley. Quercus is one of 27 cooperages left in America and adheres to the study and techniques of traditional coopering. With his spirit of ingenuity and know-how, John began adapting large scale commercial tanks to a small manageable size. Quercus began to fabricate the small scale “Kioki” filling the void of small wooden fermenting tanks in the marketplace. 

Selling to the burgeoning shoyu makers, Quercus began to get requests for traditional kojiban trays leading them to eventually develop their koji incubating “Muro Cabinet”.  The Muro gives both chefs and koji curious home cooks a perfect device to make their own koji.

In early 2025 Quercus decided to branch off their culinary pieces from the cooperage and open THE KOJI SHOP to dedicate a market place to showcase their culinary products along with koji spores, and all of the additional accessories needed for people to begin their Koji journey.