Open AccessSeed procyanidin composition of Vitis vinifera L. var. ˈCarignanˈ and ˈGrenacheˈ was analyzed to assess the impact of vintage climatology, plant vigor and bunch variability on the quality of grapes. This study was carried out over 2007 and 2008 vintages in Terra Alta denomination of origin (DO). This region is located in northeastern Spain and characterized by a Mediterranean climate with a continental tendency. Procyanidin composition of seeds from four vineyards was analyzed by rapid resolution liquid chromatography (RRLC-DAD-TOF/MS). Vintage, vigor and ripeness uniformity had an influence on the procyanidin concentration in seeds. Flavan-3-ol polymerization increased during the warm year, together with a notable dependence on the variety and vine vigor. In warmer years and low vigor, ˈGrenacheˈ seed composition is likely to be more vulnerable than ˈCarignanˈ. High levels of flavan-3-ol monomers and low polymerization characterized the seeds of the temperate year.