Red Wine Color: Relating Color to Composition in Young Wines and Predicting the Color of Aged Wines

Young red wines are considerably darker and different in color than would be expected from their pigment composition. The extent of anthocyanin copigmentation, which can account for between 30 and 50% of young wine color, is directly related to the presence of other colorless components found in the juice and especially the skins of grapes. The concentrations and identity of these copigmentation cofactors varies widely between the grape cultivars and the conditions under which they have been grown. The changes in this aspect of color due to the slow formation of polymeric pigment are reviewed. A simple model for the formation of polymeric pigment and these changes in color is presented. The role of the colorless cofactors and tannin, and winemaking practices which influence these, on the color displayed by young and aged red wines is described.