Unlike pigments extracted from fresh grape skin or whole grapes, GrapEX skin tannin contains a large concentration of complex wine pigments (pigmented tannins). These complex tannins are formed during the winemaking process and are responsible for maintaining the colour of red wine during aging.


Isolation and structures of Oligermeric Wine pigments by Bisulfite-Mediated Ion Exchange Chromatography; G. P. Jones, et al:J.Agric Food Chem., Vol. 49, No.12, 2001pp.