Future scenarios for viticultural climatic zoning in Europe

Secondary (or specialised) metabolites such as terpenes and phenolic compounds are produced by plants for various roles which include defence against pathogens and herbivores, protection against abiotic stress, and plant signalling. Additionally, these metabolites influence grapevine quality traits such as colour, aroma, taste, and nutritional value. However, the biosynthesis of these metabolites is often complex and controlled by multiple genes which in grapevine are predominantly uncharacterised.

Sulphur dioxide has long been considered an irreplaceable additive due to its numerous significant positive effects during winemaking and beyond.

According to the different concern of the ‘traditional’ and the ‘new’ wine-producing Countries, a variable importance is recognized to the climate/soil and to grapevine cultivars as factors affecting the wine quality. However, the viticultural experience can state that, within each area, climate and soil plays an incontestable role in affecting grape quality, and consequently wine quality, as well as the genetic characteristics of the cultivar.

Planting vineyards in cooler climates has been used over recent years as
a strategy to counter the climatic shifts caused by climate change. A move towards higher altitudes in hilly and mountainous wine regions may provide a solution to deleterious effects that increased ambient temperatures have on wine quality. Until now, the influences of higher altitudes and their climates, as well as their effect on vine growing cycles, still holds a lot of scientific uncertainty. The transnational EU-funded project REBECKA (Interreg V-A IT-AT: ITAT1002, duration: 2017-2019) has the objective to develop a regional valuation method to rate the suitability for viticulture in South Tyrol (Italy) and Carinthia (Austria). Preliminary surveys were performed regarding the effects of altitude on ripening performance of the cultivar Pinot Noir.

A consequence of climate change is the modification of grape harvest quality and physico-chemical parameters of the obtained wine: increase in alcoholic degree, decrease in pH, and modification of the extractability of macromolecules, which leads to problems of microbiological, tartaric, colour and colloidal stability. In order to respond to these problems, the winemaking processes must be anticipated and adapted with a better knowledge of macromolecule extractability in grapes and their evolution, according to the grape variety, vintage and winemaking process. The purpose of this study was to understand 1) how the harvest date can influence the extractability of macromolecules, polysaccharides and phenolic compounds, which are responsible for wine stability 2) how to adapt the winemaking process to the harvest date in order to optimise wine quality.