Variation of the climatic conditions among years is one of the most important factors having influence on wine composition and quality. This work evaluated the effect of the 1999, 2000, and 2001 vintages of the Isabel grape, must, and wine composition from Serra Gaúcha, Brazil. In this way, twenty-two grape growers from 11 communities of this region were taken. From each grower, 60kg of ripened grapes were sampled from which evaluations on grape and must were performed and microvinifications were made. Results showed that the vintage had a significant effect on cluster and berry weight, but there was no effect on stem/cluster weight ratio. In the same way, there was differences on the majority of the variables of the must of Isabel studied, exception to the °Brix/total acidity ratio. It also had effect on the majority of the variables of the wine, exception to the K, Mn, Cu, and Rb cations. In general, the 1999 vintage was better, because it showed more adequate parameters for total acidity, dry extract, reduced dry extract, alkalinity of ashes, tannins, anthocyanins, and glycerol, variables that determine wine structure and color, important factors for wine quality.
vintage; chemical composition; climatic factors; Vitis labrusca
