A climate-driven framework for interpreting Cabernet-Sauvignon vintages in the Maipo Valley (Chile) using chemical and bioclimatic markers

Abstract

Understanding the climatic drivers of vintage variability is essential for interpreting wine typicity under climate change, as climate strongly influences grape composition and wine quality. This study evaluates the relationships between seasonal climatic conditions and the chemical composition of commercial Cabernet Sauvignon wine from the Maipo Valley (Chile) across four consecutive vintages (2017–2020), aiming to identify climate-sensitive chemical markers that enable vintage discrimination.

Climatic characterization was conducted using accumulated bioclimatic indices, including cold stress hours (EFA, <10 °C), photosynthetically active hours (HEPA, 10–30 °C), heat stress hours (STA, >30 °C), and growing degree days (GDD). The studied vintages exhibited contrasting thermal regimes, with 2017 and 2020 classified as warm seasons, whereas 2018 and 2019 were closer to long-term averages; however, 2019 showed notably higher cold stress.

Wine samples were subjected to comprehensive chemical characterization. Total phenolic content and chromatic parameters were determined by UV–visible spectrophotometry. Individual phenolic compounds, including anthocyanins, flavan-3-ols, flavonols, and hydroxycinnamic acids, were quantified by high-performance liquid chromatography with diode array detection (HPLC-DAD). Key volatile compounds were analysed by gas chromatography coupled with mass spectrometry (GC-MS).

Multivariate analysis using principal component analysis (PCA) explained up to 78 % of the total variability, identifying phenolic maturity and aromatic freshness as the main drivers of vintage discrimination. Vintages associated with more favorable thermal conditions (2018–2019, higher HEPA accumulation) were characterized by higher concentrations of polymeric pigments, flavanols, flavonols, and increased color intensity. In contrast, the warm 2017 vintage, marked by elevated heat stress, exhibited reduced color development and higher levels of flavonols such as quercetin and kaempferol. The 2020 vintage, also warm, was differentiated by higher tannin content and enhanced concentrations of fruity and floral aroma compounds, including β-damascenone and β-ionone. Elevated cold stress during the 2019 season was associated with increased levels of IBMP and 1,8-cineole, contributing to a fresher aromatic profile.

Overall, these results demonstrate that integrating bioclimatic indices with robust chemical markers provides a reliable framework for discriminating vintages in commercial wines. This integrative approach enhances the interpretation of phenolic and aromatic signatures in relation to climate variability and offers valuable insights for vineyard management, harvest decisions, and terroir characterization under ongoing climate change.

References

van Leeuwen, C., & Darriet, P. (2016). The impact of climate change on viticulture and wine quality. Journal of Wine Economics, 11(1), 150–167. https://doi.org/10.1017/jwe.2015.21

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