A multivariate methodology to distinguish among wine Appellations of Origin

Abstract

The legal recognition of the geographical origin of wines, named Appellation of Origin, is of great interest for both consumers and producers, since it provides decisive criteria of acceptability in terms of guaranteed quality. However, when wines are considered to differ among the viticultural regions where they are produced, it is difficult to verify if the distinction is actually linked to their provenance, or, conversely if it is merely due to the work of the winemaker. Therefore, there is a need for methods that separate the effect of the geographical location from that of the human factor. Thirteen Merlot and 14 Cabernet Sauvignon vineyards were selected from two Appellations of Origin, named Binissalem and Pla i Llevant, located in the Balearic Islands (Spain). Grapes and soils were sampled evenly over the whole surface of each vineyard. Climatic and landscape conditions were also registered at each site. Univariable analysis was performed to evaluate the effect of the Appellation of Origin on the color intensity, the color tonality and the phenolic content of grapes, the silts, sands, clays and carbonate content of soils, the rainfall, the maximum and minimum temperature, and the elevation of the vineyards in 2009 and 2010. Based on the soil, climate, and landscape characteristics, a Partial Least Square Discriminant Analysis was used to discriminate between both Appellations of Origin. Results showed that a particular agroclimatic terroir may be defined for each Appellation of Origin. Indeed, this multivariate analysis led to a correct classification rate of 95 % for both 2009 and 2010 models and a prediction accuracy higher than 85.7 %. The research here proposed a methodology suitable for evaluating the appropriateness of contiguous viticultural Appellations of Origin in terms of a whole terroir concept, without considering the human factor.