Evolution of grapes’ titratable acidity and sugar content in relation to canopy microclimate in the Cotnari wine growing region conditions

Abstract

High temperatures and high values of solar radiation during grape ripening lead to excessive sugar accumulations and low titratable acidity, with negative consequences on the sensory profile of the grapes and wines. The control of these unfavourable developments for the chemical composition of the grapes becomes a base condition for obtaining quality wines in the context of climate change. The research was carried out in 2020, on Tămâioasă românească wine grape variety in the Cotnari wine growing region, during the grape ripening season. The study revealed: positive correlations between the helio-thermal factors and grapes sugar content; negative correlations between the same climatic factors and grapes titratable acidity; and the influence of some cultural practices on grapes chemical composition. The grapes on the west side of the row have accumulated less sugars during ripening: 137.64 g / L on the west side and 145.72 g / L on the east side; grapes acidity on the west side was also more pronounced, with 13.61 g / L tartaric acid compared to 12.69 g / L tartaric acid on the east side. The 6% bentonite film treatment reduced the impact of temperatures and solar radiation on titratable acidity of the grapes, maintaining it by 0.83 g / L tartaric acid higher than the control.