Late pruning, an alternative for rainfed vine varieties facing new climatic conditions

The production of most red wines that are sold involves an alcoholic fermentation carried out by yeasts of the Saccharomyces genus, and a subsequent fermentation carried out by lactic bacteria of the Oenococus oeni species after the first one is fully completed. However, the traditional process can face complications, which can be more likely in grape juices with high levels of sugar and pH. Because of climate change, these situations are more frequent in the wine industry. The main hazards in those scenarios are halts or delays in the alcoholic fermentation or the growth of unwanted bacteria while the alcoholic fermentation is not done yet and the wine still has residual sugars.

The increased intensity and frequency of heatwaves, coupled with prolonged periods of drought, are a significant threat to viticulture worldwide. During these conditions the more exposed leaves can show visible symptoms of heat damage. We monitored the functionality of photosystem II (PSII) in the field to better understand the impact of heatwaves on canopy performance. A factorial experiment was established in summer 2023 using Shiraz grapevines in the Barossa valley of South Australia, involving water-stressed and well-watered vines.

Ultra-High Pressure Homogenization (UHPH) is an innovative, efficient and non-thermal technology that can be applied at different stages in winemaking in order to reduce or avoid the use of sulphites. During 2022 vintage, a batch of Xarel·lo must was processed by UHPH at 300 MPa with an inlet temperature (Ti) of 4 ºC. In order to verify the influence of the UHPH treatment in wine characteristics, alcoholic fermentations with this must (UHPH) were carried out and compared with a control batch (without SO2 addition (C)) and a sulphited batch, in which 60 mg/L of total SO2 (SO2) were added.

The main objective of the work was to develop a simple, robust and selective analytical tool that allows predicting the authenticity of Tempranillo wines from DOCa Rioja. The techniques of voltammetry and absorbance-transmission and fluorescence excitation emission matrix (A-TEEM) spectroscopy have been applied in combination with machine learning (ML) algorithms to classify red wines from DOCa Rioja according to region (Alavesa, Alta or Oriental) and category (young, crianza or reserva).

Grape and wine phenolic compounds have been shown to be highly related to both wine quality (color, flavor, and taste) and health-promoting properties (antioxidant and cardioprotective, among others). The aim of this work was to evaluate and compare the phenolic contents of Cabernet Sauvignon wines from different geographical areas and climatic conditions, namely from Argentina, Portugal and Spain vintage 2022. In addition, the phenolic profiles of the Portuguese wines from three vintages (2020, 2021, 2022) was compared.