The effect of grape ripening stage on red wine color

Abstract

The physico-chemical and chromatic characteristics of grapes (Vitis vinifera L. cv. Monastrell) harvested at six different degree of ripeness (from August 16 to October 24, 2002) and that of the wines obtained from these grapes have been studied. The grape anthocyanins content (mg/kg of berry fresh weight) was maximum in those grapes harvested on September 11 and 16 (804.1 and 822.6 mg/kg, respectively) and decreased for grapes harvested in October. However, the results showed that the grapes with the highest anthocyanin concentration did not lead to the highest colored wines. The wines elaborated from grapes harvested on October 16 (671.9 mg of anthocyanins per kg of berry fresh weight) had the best chromatic characteristics and better withstood aging in the bottle; the extent of cell wall degradation in overly matured grapes probably facilitated the extraction of phenolic compounds from skins. However, the chromatic quality of wines made from grapes harvested one week later (October 24, the most mature grapes) was lower than that from October 16, with lower color intensity (13%lower in the wine elaborated from grapes harvested in October 24) and a percentage of yellow color 6 % higher in this wine.