Chemical evolution of wine from a new Brazilian terroir: Metabolomic insights into vinification and aging processes

The development of grapes and the resulting wine are influenced by environmental factors associated with vintage, such as temperature, rainfall, and sunlight, which affect key metabolites including sugars and phenolics. In addition, winemaking processes, such as fermentation and barrel aging, further shape the final wine profile. In Brazil, the Vitis vinifera 'Syrah' cultivar is particularly prominent, especially in the state of São Paulo, where the double-pruning technique has been adopted to mitigate the challenges of tropical summer rainfall. So far there are no other studies on this subject and we believe this is the first metabolomic study focused on 'Syrah' wines produced from double-pruning vineyards in Brazil, offering a valuable reference for future research on 'Syrah' and other grape varieties and winegrowing regions. Using untargeted LC-MS metabolomics, a total of 31 metabolites were annotated across the 2022 and 2023 vintages. Multivariate statistical analyses (PCA and OPLS-DA) revealed clear differentiation in the chemical profiles among vintages, vineyard plots, and aging in different French oak barrel brands. Key secondary metabolite classes contributing to this separation included ellagitannins, such as ellagic acid (VIP = 7.610) and vescalagin (VIP = 3.174), and anthocyanins such as malvidin-3-glucoside (VIP = 2.748), malvidin-3-(6″-p-coumaroylglucoside) (VIP = 2.253), and peonidin-3-O-(6″-p-coumaroyl-glucoside) (VIP = 1.208), which varied significantly according to barrel type and vintage. Notably, the oxygenated sesquiterpene rotundone (VIP = 3.336), responsible for the characteristic "pepper" aroma of 'Syrah' wines, was identified for the first time in winter wines produced via the double-pruning method, highlighting a unique aromatic feature of this viticultural approach. These results underscore the combined influence of climatic variation and aging strategy on the wine metabolome and provide a molecular basis for optimizing barrel selection and vintage characterization in emerging wine regions.