How terroir affects bunch uniformity, ripening and berry composition in "Vitis vinifera" cvs. Carignan and Grenache

Aims: Vineyards from early and late terroir were evaluated during ripening to determine optimal grape composition, with special emphasis on bunch uniformity. Methods and results : Four treatments were studied over three years : Carignan and Grenache in two terroir, early and late. Samples were divided into two parts (top and bottom half of the bunch) in order to determine berry weight, sugar content, titratable acidity, total and extractable anthocyanins, total phenols, and seed maturity. The results showed bunch uniformity in Carignan. The kinetics of berry maturity generally showed a straight line pattern in Grenache while in Carignan it varied. For both cultivars, berry weight and yield were higher in the late parcel, whereas anthocyanins were more concentrated in the early terroir. Conclusion: Pulp maturity is less influenced by the terroir effect than phenolic maturity. Vintage or terroir affect Carignan more consistently than Grenache. Carignan does not achieve complete phenolic ripeness in the late mesoclimate. In warm years, Grenache grapes should be gathered as soon as the pulp reaches the optimal sugar level because the accumulation of anthocyanins does not improve when the harvest is delayed beyond that point. Significance and impact of the study: The evaluation of phenolic maturity in relation to terroir and bunch uniformity contributes to defining ideal harvest time and optimizing winery management.