Stability in Wine Differentiation of Two Close Viticultural Zones

Abstract

Pattern recognition techniques were applied to the discrimination of wines from two very close viticultural regions. They are two zones in the Utiel-Requena region (Valencia, Spain) of Certified Origin centered in the Utiel and Requena towns, respectively. The differentiation is due to various climatic factors, since soil characteristics are very similar and the cultivars are the same. This climatic differences influence the degree of ripeness attained The differences in altitude of the zones account for their climatic differences. This study focused on data corresponding to rosé wines (Bobal cultivar) from the 1988 vintage. Discriminant analysis showed that four variables (ethanol, anthocyanins, K, and Na) allowed a satisfactory zone classification of these rosé wines (93.5% well classified). The application of the discriminant analysis results to a series of wines of the same year, not considered previously, has also led to successful results (90.6% well classified). In order to evaluate the discriminant power of these variables, the study was broadened to include a longer period (1987-1994). In each case, the analysis was similar although data used were only those corresponding to the four variables above-mentioned. In all cases, the classification was acceptable (90.7% well classified on average and better than 81% in each individual case), thus showing the stability of the discriminant variables along a period of eight years. The influence of the climate (year) is demonstrated through the variation of the discriminant variables coefficients.