is an umbrella term for substances, that are easily soluble in water. The occured watery dissolution is characterised by its astringent effect and the property to tan leather. Chemically speaking it is not a simple substance, but an accumulation of complexe organic matter, that is contained in fruits, wood and bark of various trees and various shrubs. Therefore it is also termed as natural product. For industrial use tannic acid is extracted from bark of various trees and mostly used in watery solution. Tannins are seperated into different qualities, depending on their purity. Depending on the quality the range of application varies.