Towards faultless Grenache wines: impact of climate and maturity

Abstract

Climate change is affecting wine production and inducing significant variability in wine composition between vintages. These effects are often seen in altered precipitation patterns and higher temperatures during maturation, leading to a decoupling between technological and phenolic maturations, which results in delays, high sugar concentrations and aromatic defects at harvest. Such phenomena are particularly evident in Grenache, a cultivar well-represented in France and Spain within the POCTEFA Pyrenean foothills. The aim of this study was to investigate over two consecutive seasons, the impact of climate and maturity on the aroma of wines made from this cultivar.

For the main Protected Designation of Origin (PDO) areas with Grenache cultivars located in the POCTEFA region (Aragn, La Rioja, Navarra, País Vasco, Cataluña and Pyrénées-Orientales), climatic data from 1981 to 2010 were collected and used to calculate several bioclimatic variables. Data were analysed using k-means clustering to identify three homogenous climatic zones. A stratified sampling approach was employed to select 30 Grenache vineyards across Spain and France (20/10), corresponding to the three previously identified climatic zones (10/10/10). For each site, grape samples were harvested at three maturity stages: the first at a sugar concentration of 21.0 ± 2.0 °Brix (P1), the second one (P2) 12 ± 2 days after P1, and the third (P3) 12 ± 2 days after P2. These grapes were used to determine classical oenological parameters, to monitor phenolic composition according to the Cromoenos® method, to obtain a berry volatile fingerprint through SIFT-MS analysis and to produce hydrolysed mistelle – a model to predict the aroma potential of grapes by GC-MS [1]. At P1 and P2, experimental wines were produced under minivinification techniques to analyse wine aroma composition using GC-MS techniques and to perform sensory analysis.

Currently, only data from the 2024 harvest are available. The findings emphasize the importance of climate and maturity on aroma composition and enable to determine optimal climatic conditions to avoid the appearance of aromatic defects. In a future, these findings will also be useful to identify new viticultural regions, more suitable for the future production of faultless wines in a context of changing climate.

Funding

This work is part of the EFA102/01 CLIMAROMA project, 65% co-financed by the European Union through the Interreg VI-A Spain-France-Andorra Programme (POCTEFA 2021-2027).

References

[1] Alegre, Y., Arias-Pérez, I., Fernández-Orte, P., Ferreira, V. (2020). Food. Res. Int., 127, 108728.