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.

Experiments1 have shown that many complex wine pigments are selectively removed with the marc during the winemaking process and subsequently extracted and concentrated into GrapEX™ liquid tannin.

1. 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.