Red wine oxidation study by accelerating ageing tests and electrochemical method

Young white wines are typically released to the market a few months after harvest, to be consumed within a year, when their fresh fruity aromas are still dominant and appealing to modern consumers. Esters, particularly higher alcohol acetates (HAAs) and ethyl esters of fatty acids (EEFAs), play a central role in the fruity expression of young white wines [1]. However, these esters are known to undergo significant hydrolysis during the first months of aging [1, 2].

The study was carried out in 2006 with Merlot grapes from vines grown using the trellis system, where four treatments were compared with different levels of water stress.

The seasonal’s climatic conditions determine the composition of grapes at harvest as they affect the vine’s physiology and development. High temperatures during the grape ripening period cause a high accumulation of sugars and degradation of fruit acidity ,and alter the synthesis of polyphenols. Therefore, some vineyard management can be applied in order to modify grapevine impact on climate variability. One example is the pre-pruning at the beginning of grape ripening, which can delay the ripening period and modify the composition of the grapes at harvest. This work aims to evaluate the pre-pruning field technique on yield components and alcohol content in wines of Tannat and Merlot varieties.

Wine produced under Designation of Origin (DOP) Ribeiro, the oldest DOP in Galicia (NW Spain), are elaborated using local grape cultivars, grown at the valleys of Miño, Avia and Arnoia rivers. The landscape formed by slopes and terraces and the peculiar climate of continental character, softened by the proximity of Atlantic Ocean, make it an area of excellent aptitude for vine cultivation. In addition, small-scale farming and the use of traditional techniques for vineyard management provide a great diversity to Ribeiro wines. This study presents the evaluation of red and white wines (bottled or bulk wines) from DOP Ribeiro, produced between years 2018-2022.

Climate change is leading to an increase in average temperature and in the severity and occurrence of heatwaves, and is already disrupting grapevine phenology. In Australia, with the evolution of the weather of grape growing regions that are already warm and hot, berry composition including flavonoids, for which biosynthesis depends on bunch microclimate, are expected to be impacted [1]. These compounds, such as anthocyanins and tannins, contribute substantially to grape and wine quality. The goal of this research was to determine how flavonoid extraction is impacted when bunches are exposed to high (>35 °C) and extreme high (>45 °C) temperatures during berry development and maturity.