The first written history of vinegar dates back to China in 1200 BC. In ancient Greece, around 400 BC, Hippocrates, who is considered the father of modern medicine, prescribed apple cider vinegar mixed with honey for a variety of ailments, including coughs and colds. The Japanese samurai believed drinking a rice vinegar drink would boost their strength and they drank it regularly (Enzyme-Facts.com).
Real Japanese rice vinegar is around 4% acidity. Most vinegars used in Japan today are actually a blended combination of wheat, corn, rice vinegars with sake kasu (the thick rice paste left at the end of the sake making process also called sake lees), and alcohol. The distinction between the “true” original rice vinegars and their blended counterparts is almost never known and probably not even known anymore. Kurozu (black vinegar) has a dark amber color and is made from brewing rice vinegar produced from unpolished rice with rice bran through static-surface acetic acid fermentation. The brewing process for Kurozu is very distinctive compared to rice vinegars. Its entire brewing process proceeds spontaneously within the same pot outdoors in a natural environment for over a year. This contributes to Kurozu’s high amino acid concentration, vitamins, organic acids, and proteins than rice vinegar. Kurozu has been shown in rats to decrease adipocyte size (Tong, et al.). Authentic Kyushu brown rice accounts for less than 1 percent of Japan’s annual 100 million gallon vinegar production. The quicker industrial rice vinegar-making process does not use rice koji; instead it adds sake lees which is fermented under controlled temperatures and, in less than a month, bacteria convert the alcohol to acetic acid (distilled vinegar) (Mitoku). Since the industrial rice vinegar process distills the alcohol by boiling, so most of the amino acids are destroyed. Rice vinegar contains no calories, no fat, and no sodium and is perfect for enhancing the flavor of rice without adding any extra calories and is also good for making homemade salad dressings.
References
Enzyme-Facts. Vinegar – The History. http://www.enzyme-facts.com/vinegar-history.html. Accessed 5 November 2014.
Mitoku. Health Benefits of Brown Rice Vinegar: Kyushu Brown Rice Vinegar. http://www.mitoku.com/products/ricevinegar/healthbenefits.html. Accessed 5 November 2014.
Tong, L-T, Katakura, Y., Kawamura, S., Baba, S., Tanaka, Y. (2010). Effect of Kurozu Concentrated Liquid on Adipocyte Size in Rats. Lipids in Health and Disease. (9)134.