Influence of precipitation on the phenolic and isotopic composition of Vitis Vinifera red wines
Abstract
This study investigates how precipitation from November to February during each harvest year, influence the phenolic and isotopic profiles of red wines, particularly focusing on trans-resveratrol, total phenolic compounds, and carbon and oxygen isotopes (¹³C/¹²C and ¹⁸O/¹⁶O). Wines from Merlot, Cabernet Sauvignon and Cabernet Franc grapes, grown in Rio Grande do Sul (Brazil) and produced between 2020 and 2023 on a laboratory scale, were analyzed. Phenolic compounds, important for wine quality and human health, were quantified using spectrophotometry, with resveratrol levels assessed via high-performance liquid chromatography (HPLC). Isotopic compositions were measured using isotope ratio mass spectrometry (IRMS). Among the varieties, Cabernet Franc showed the strongest correlations: its resveratrol, total phenolic content and 18O/16O were closely linked to January precipitation, while a strong relationship between 13C/12C and resveratrol was also observed. In contrast, Merlot and Cabernet Sauvignon showed minimal climatic influence on these variables. These findings highlight Cabernet Franc’s sensitivity to the accumulated precipitation in January, close to its harvest, and its potential as a marker for environmental influences. Future research will incorporate 2024 data and expand to other regions of Rio Grande do Sul.
DOI:
Publication date: September 22, 2025
Issue: 46th World Congress of Vine and Wine
Type: Short communication
Authors
1 Laboratório de Referência Enológica Evanir da Silva (LAREN/SEAPI). Avenida da Vindima, 1855 – Exposição, 95084-470 Caxias do Sul, RS, Brazil
2 Universidade Estadual do Rio Grande do Sul. Campus Central, Rua Washington Luiz, 675. Centro Histórico, 90010-460 Porto Alegre, RS, Brazil