【Reading】あかず

【English Name】Akazu (Red Vinegar)

Akazu (red vinegar) is the common name for vinegar brewed from sake lees (sake kasu) as its raw material. It came to be called by this name because the finished product takes on a reddish-brown color. Its formal name is "kasuzu," and under JAS (Japanese Agricultural Standards) labeling it is classified as grain vinegar.

Behind the birth of akazu lies the high price of rice vinegar in the Edo period. Rice vinegar made from rice and koji was extremely expensive and hard for common people to afford. Thus Nakano Matazaemon, founder of Mizkan—known for vinegar brewing—is said to have focused on sake lees, a by-product of sake brewing, and begun producing kasuzu using it as the raw material.

The appearance of cheaply available akazu greatly contributed to the development of Edomae nigiri sushi. Used in vinegared rice, it added a distinctive mellow acidity and deep color, becoming the foundation of the flavor of Edomae sushi.

However, after the war, the distribution of kasuzu greatly declined due to factors such as material shortages and the yellow-rice incident, and rice vinegar instead became the mainstream sushi vinegar. In recent years, akazu has been re-evaluated mainly by artisans aspiring to traditional Edomae sushi, and cases of its use at discerning sushi restaurants are increasing.