The hydrolysable tannins are further divided into gallic and ellagic tannins. The first, the gallotannins release glucose and gallic acid by hydrolysis in low ambient pH. They are mainly extracted from Tara (Caesalpinia spinosa) and gallnuts (Quercus infectoria and Rhus semialata) and they present a creamy or yellowish color. The gallic tannins are not very astringent and have a bitter taste.
The ellagitannins, made from ellagic acid glycosides, are one of the components of oak wood (Quercus robur, Quercus petraea and Quercus alba) and chestnut wood (Castanea sativa). They have a darker color compared to the gallotannins. The ellagic tannins are also less astringent and they have a distinctive wood scent. Ellagitannins are not present in wine unless transferred from the wood of the barrels.
The condensed tannins have a reduced astringent power and a high ability to release the aromatic precursors present in wines. Condensed tannins are divided into proanthocyanidin and profisetinidin. Proanthocyanidins are naturally present in grapes (Vitis vinifera) consisting of various flavonoids which release anthocyanins and other insoluble molecules when they are treated with acid hydrolysis. They are mainly diffused in the skins and seeds of grape, and therefore you can find them in red wines. Profisetinidins are extracted from the quebracho wood (Schinopsis lorentzii) and mimosa (Acacia mollissima).