The Mediterranean climate of The Priorat AOC, situated behind the coastal mountain range of Tarragona, tends towards continentality with very little precipitation during the vegetation cycle. The soil is poor, dry and rocky, largely composed of slate schist, known as “llicorella”. Vines primarily grow on steep slopes and terraces.
To evaluate how the Priorat unique terroir influences the quality of its wines, two plots of Grenache were chosen, both grafted onto R110. In the study those two sites are referred to as: LO (in the township of Lloar) and EM (in the township of Molar), distinct topographic locations within the AOC. Grenache vines in LO are 14 years old growing in east-south facing terraces. Grenache vines in EM are 16 years old, and south-facing. Both vineyards feature VSP trellising with 2 wires (70cm height). The vines are pruned as bilateral cordon. During 2010 and 2011, leaf area (LA) at the phenological stages of pea size (PS), veraison (V), final ripening (RP) and post-harvest (PH) was measured. Berry phenolic maturity was monitored and the chemical analyses of the wine were carefully evaluated.
The 2010 vintage was characterized by a heterogenic distribution of rainfall and a lower vapor deficit pressure than 2011. Total leaf area (TLA) within parcels did not differ significantly in the temperate year. In the drier vintage, however, vines from LO developed more leaf area than those growing in the south-facing terraces at EM. Nevertheless, the total leaf area before harvest was similar. The heterogeneity in the soil profile at the LO location could likely induce a variation in the drainage capacity, affecting the vine growth (TLA). Small berries from EM produced the highest levels of anthocyanins. EM always has the highest content in ANT T, ANT E, IPT and DMACA in both years. Concerning the wines, the highest concentration of anthocyanin were found in the EM treatment, with greater differences that LO in 2010. Grenache vines growing under warm climate conditions (Priorat AOC), in heterogeneous-stony soils, showed notably variability in the wine composition in front of climate change.
Authors: Montserrat NADAL and Antoni SANCHEZ-ORTIZ
Dept Bioquímica i Biotecnologia, Facultat d’Enologia de Tarragona, URV. Campus Sescelades, 43007 Tarragona, Spain.
Keywords: Priorat, Grenache, vapor pressure deficit, stony soil, schist, phenolics