Long-term dynamics of grape acidity under climate variability: evidence from Chardonnay in Bourgogne vineyard

Abstract

Recent climate warming has profoundly affected grape composition, with a general decrease in acidity and an increase in must pH widely reported across winegrowing regions. These changes are mainly attributed to enhanced malic acid degradation during ripening under elevated temperature conditions and, in many cases, water deficit (Sweetman et al., 2014). In addition, high temperatures combined with limited water availability can also reduce berry acidity, reinforcing concerns about the future balance of wines in the context of climate change (Sweetman et al., 2014). In this study, we investigated the long-term (2007-2024) evolution of must acidity in Chardonnay in Bourgogne (France) using a multiannual dataset, assessing how climatic variability and warming trends influence key acidity parameters, including titratable acidity, pH, the balance of organic acids, and their interaction with cations, particularly potassium, which plays a key role in modulating must pH. The temporal dynamics of malic acid at harvest reveal an overall decreasing trend over time, consistent with the observed warming, but accompanied by marked interannual variability. To isolate the climatic signal, a Partial Least Squares (PLS) approach was applied, focusing specifically on acidity-related variables. The PLS analysis revealed a clear structuring of vintages along a climatic gradient primarily driven by temperature and evaporative demand, with warmer conditions consistently associated with lower acidity levels. This pattern is consistent with previous studies linking temperature and vine water status to berry composition (Pasquier et al., 2021). Overall, these results confirm the strong sensitivity of grape acidity to climatic conditions while highlighting the key role of interannual variability in modulating this response, emphasizing the need for integrative approaches to better understand and anticipate future changes in grape composition under ongoing climate change.

References

Sweetman, C., Sadras, V. O., Hancock, R. D., Soole, K. L., & Ford, C. M. (2014). Metabolic effects of elevated temperature on organic acid degradation in ripening grape berries. Journal of Experimental Botany, 65(20), 5975–5988. https://doi.org/10.1093/jxb/eru343

Pasquier et al. (2021) Pasquier, G., Feilhes, C., Dufourcq, T., & Geffroy, O. (2021). Potential contribution of climate change to the protein haze of white wines from the French southwest region. Foods, 10(6), 1355. https://doi.org/10.3390/foods10061355