Rice vinegar is vinegar prepared from fermented rice or rice wine in China and Japan. Japanese rice vinegar is very soft and mellow and ranges in colour from colourless to pale yellow. There are two different types of Japanese vinegar: one is made from fermented rice and the other is made by adding rice vinegar to sake. Chinese rice vinegars are stronger than Japanese ones, and range in colour from clear to different shades of red and brown. Chinese and especially Japanese vinegars are very mild and sweet compared to purify and more acidic Western vinegars which, for that reason, are not proper substitutes for rice vinegars. White rice vinegar is colorless to pale yellow liquid, superior in vinegar content and more similar to Western vinegars, but still less acidic and milder in flavor.
Black rice vinegar is popular in southern China. Chinkiang vinegar, which originated in the city of Zhenjiang in the eastern coastal province of Jiangsu, China, is measured the best of the black rice vinegars. Usually black rice vinegar is made with glutinous rice, although millet or sorghum may be used instead. It is dark in colour, and has a deep, almost smoky flavor. In addition to Zhenjiang, it is too produced in Hong Kong.
Red rice vinegar is darker than white rice vinegar, and paler than black rice vinegar, with a typical red colour from Red yeast rice, which is cultivated with the mold Monascus purpureus. This vinegar has a distinctive flavour of its own due to the red mold. In Chinese cookbooks, ½ tablespoon of Western white vinegar is equivalent in strength to 1 tablespoon Chinkiang vinegar. Many Chinese people who grow up with rice vinegars take time to raise accustomed to the strength of Western vinegars when they begin to encounter them. Rice vinegar is also used to make sushi.