IMPACT OF CLIMATIC ZONES ON THE AROMATIC PROFILE OF CORVINA WINES IN THE VALPOLICELLA REGION

Abstract

In Italy, in the past two decades, the rate of temperature increases (0.0369 °C per year) was slightly higher compared to the world average (0.0313 °C per year). It has also been indicated that the number and intensity of heat waves have increased considerably in the last decades. (IEA, 2022). Viticultural zones can be classified with climatic indexes. Huglin’s index (HI) considers the temperature in a definite area and has been considered as reliable to evaluate the thermal suitability for winegrape production (Zhang et al., 2023).

In this scenario, understanding the relationship between climatic conditions existing in specific grape growing areas and the composition of the grapes and wines composition grown in that particular region is of major interest. The aim of this project is to investigate the aromatic profile of Corvina grapes and wines in the Valpolicella region and how it is impacted by the different climatic zones. Valpolicella is a wine-making region found in the north of Italy in the zona of Veneto, it is divided into three zones (Valpolicella Classica, Valpantena, and Orientale). All zones are subdivided into valleys and hilly areas which can range from 30 up to 500 m a.s.l., this variation in altitudes plays a role in the climatic conditions.

First, the climatic zones were studied in the region. Data from 24 weather stations across this region showed that there are 5 different HI climatic zones from temperate to too hot. Based on this information, grapes were obtained from 16 different vineyards from three different climatic zones (warm temperate, warm, and very warm), in order to carry out micro vinifications and grape macerations. Vinification was carried out in triplicate with 800 g of Corvina grape in bottles of 1 L Saccharomyces cerevisiae AWRI 796 (Experti Srl) and potassium metabisulphite was added, and fermentation was carried at 22 °C until it reached a concentration of ~1 g/L of glucose-fructose. In addition, grape macerates were also prepared to investigate the varietal compounds in the absence of yeast activity. Grape macerates were carried out in triplicate with 500 g of Corvina grapes in bottles of 1 L with ethanol (15% w/w), potassium metabisulphite, and dimethyl decarbonate at 22 °C for 15 days.

For the quantification of alcohols, esters, fatty acids, benzenoids, terpenes, and volatile sulfur compounds, a combined analytical strategy involving SPE and SPME extraction methods followed by GC- MS analysis was used. Enological parameters were measured using a Biosystems Y15 multiparametric analyzer. Results will contribute to developing tailored strategies for climate change management for Valpolicella wines.