Mesoclimate and Topography influence on grape composition and yield in the AOC Priorat

The Priorat AOC, which is situated behind the coastal mountain range of Tarragona, is characterised by a Mediterranean climate that tends towards continentality and has very little precipitation during the vegetation cycle. The soil is poor quality, dry and pebbly, and made up of schist. To measure how topographie and mesoclimate affects the qualitative potential of Grenache in the Priorat, we evaluated the changes on grape composition during ripening and at harvest. The study was carried out during the 2002 (temperate) and 2003 (warm) vintages and the trial was performed in 8 plots: two villages in two different mesoclimates were selected, early and late ripening and, two different terraces in each village, topographically located up and down of the slope. Alcohol degree, acidity, pH, skin anthocyanins, the anthocyanin content in the berry and the berry weight were sampled and analyzed during maturity. Yield was determined at harvest. Sugar content increased in early regions and cooler vintage, however, in late regions, the noticeable increase happened in the warmer vintage. Extractable anthocyanins in berries increased during ripening in early region and cooler vintage, nevertheless, the accumulation stopped o decrease a week before harvest in the warmest regions. The plot located in high altitude (late region) didn’t attaint the complete maturity as such showed the low anthocyanin concentration. Topography effects revealed higher concentration of anthocyanins, low yield and low berry weight associated to the terraces located in the up side of the hill in temperate vintage. The warm vintage affects grape composition decreasing anthocyanins and yields. No effect was found comparing early and late regions for both, yield and vintage.