Sensory changes in wines associated with the ripening of Grenache grapes from vineyards in different climatic zones

Abstract

Climate change is introducing a high variability on grape ripening, causing uncertainty, excessive spending on pesticides and eventually frustrating results in terms of the quality of the vintage, with the increasingly frequent appearance of aromatic problems associated with overripeness, raisining and greenness, which sometimes only appear in bottled wines. These effects are particularly evident in Grenache, a variety widely grown in France and Spain. This study aimed to explore the effects of climate and maturity on the sensory characteristics of wines made from Grenache over two consecutive harvests of the Pyrenean foothills.

Firstly, historical climatic data (1981 – 2010) were gathered to calculate various bioclimatic variables. The data was analysed using k-means clustering to identify three distinct climatic areas. Then, 28 Grenache vineyards (20 from Spain and 8 from France) were selected, ensuring representation across the three identified climatic zones. At each vineyard, grape samples were collected at two maturation stages: the first when sugar concentration reached 21.0 ± 2.0 °Brix (P1), and the second 10-14 days later (P2). Microvinification of the collected grapes followed the same fermentation protocol. To explore the sensory space of the wines, two Sorting Tasks were carried out, one per ripening. MultiDimensional Scaling (MDS), Agglomerative Hierarchical Clustering (AHC) and Corresponding Analysis (CA) were used to manage the sensory data. The most different wines were selected to carry out a Descriptive Analysis (DA). In order to interpretate sensory data, analysis aroma compounds in wine were carried out. The preliminary results of year 2024 indicate that wines from grapes from different climatic zones evolve differently with ripening. Descriptors with vegetal and oxidative notes are found in the cooler climatic zones, specially at point 1. This could be related to a lack of phenolic maturity and an increase in oxidation-linked compounds such as aldehydes, as previously described in the literature [1]. Whereas more fruity and overripe aromas are found in warmer areas. These attributes have been found in all climate zones at maturity point 2. The outcomes of this research will highlight the influence of climate and maturity on wine aroma composition, help determinate the ideal climatic conditions and create tools to mitigate the effects of climate change.

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] Ferrero-del-Teso, S., Arias, I., Escudero, A., Ferreira, V., Fernández-Zurbano, P., & Sáenz-Navajas, M.-P. (2020). Effect of grape maturity on wine sensory and chemical features: The case of Moristel wines. LWT, 118, 108848.