Coping with extreme climatic events: some lessons from recent work on grapevine under heat peak

The production of fermented alcoholic beverages involves numerous processes in which microorganisms and enzymes convert components derived from the raw material into a wide range of compounds that affect the sensory characteristics of the resulting product. It is estimated that there may be as many as 800 to 1,000 such compounds in wine. These compounds belong to different chemical groups such as esters, alcohols, carboxylic acids, carbonyl compounds, polyphenols, sugars and many others.

Global warming due to greenhouse gases (GHG) has become a serious worldwide concern. The new EU green deal aims to achieve GHG emissions reduction by at least 55% by 2030 and a climate neutral eu economy by 2050. The deal strongly encourages GHG reducing measures at local, national and european levels. The redwine project will demonstrate the technical, economic and environmental feasibility of reducing by, at least, 31% of the CO2 eq.

High concentration of sugars in grapes and alcohol in wines is one of the consequences of climate change on viticulture production in several wine-growing regions. In order to investigate the possibilities of adaptation of vineyard management practices aimed to reduce the accumulation of sugar during the maturation phase without reducing the accumulation of anthocyanins in grapes, a study with severe shoot trimming, shoot thinning, cluster thinning and date of harvest was conducted on Merlot variety in Istria region (Croatia), under the Mediterranean climate. Four factors which may affect grape maturation and its composition at harvest were investigated in a two-years experiment; severe shoot trimming applied at veraison when >80% of berries changed colour (in comparison to untreated control), shoot thinning (0 and 30%), cluster thinning (0 and 30%), and the date of harvest (early and standard harvest dates). Shoot thinning had no significant impact on berry composition, despite the obtained reduction in yield per vine. Lower Brix in grapes were obtained with earlier harvest date and if no cluster thinning was applied, although at the same time a reduction in the concentration of anthocyanins in berries was observed in these treatments. On the other hand, if severe shoot trimming was applied when >80% of berries changed colour, a reduction of Brix was obtained without a negative impact on berry anthocyanins concentration. We conclude that in cases when undesirably high sugar concentrations at harvest are expected, severe shoot trimming at 80% veraison may effectively be used in order to obtain moderate sugar concentration in berries together with the adequate phenolic composition.

The article presents the results of a study on the technological features of producing sparkling wines of the Pétillant Naturel (Pet-Nat) type, made using the ancestral method from the Muscat Ottonel and Pinot Noir grape varieties.

Context and purpose of the study. In regions where grapevines are grown under irrigation, like most regions in Argentina, the wine industry should adopt more sustainable strategies and production systems towards a higher water use efficiency and a reduction in no-renewable energy consumption.