A family business now run by the fourth generation, Marusho's vinegar brewery is located in the same building where they began in 1879. Mud walls and earthenware floors house giant cedarwood barrels, some more than 100 years old, where the fermentation of the vinegars takes place. Vinegars are made with fresh, soft water from the Nachi Waterfall in the nearby Kumano mountains of Wakayama. This water is delivered by a natural spring that surfaces inside the Marusho brewery.

The progress of the fermentation is minutely monitored by skilled craftsmen, this can be as long as 500 days for some of the vinegars. Marusho are renowned for the authentic and sophisticated flavour of their traditional rice vinegars seasoned with high quality natural ingredients like kombu seaweed, katsuobushi fish flakes and mirin. The quality and consistency of these vinegars means they are used by master sushi chefs in Japan and Michelin starred chefs throughout the world.

Marusho also produce a selection of ponzu sauces that display an exceptional balance of citrus and umami using ingredients like yuzu, sudachi, soy sauce, mirin, kombu and katsuobushi. These are traditionally used as a dip but also make excellent dressings for salads.