Drought responses in Chardonnay and Sauvignon blanc grapevine cultivars: Mechanistic insights and varietal contrasts

AIM:Valpolicella is a wine region located in Italy north-east, famous for the production of dry and sweet red wines from withered grapes, including Amarone and Recioto. The aim of this study is to understand the influence of the withering process on Corvina and Corvinone wines aroma profiles. METHODS:Wines were produced with a standard red wine winemaking protocol with Corvina and Corvinone grapes from different Valpolicella vineyards and vintages. In consideration of the local traditional practice of post-harvest withering of the grapes, wines from each vineyard were obtained from either fresh and withered grapes. Wines were analysed by Solid Phase Extraction and Solid Phase Micro Extraction gas chromatography coupled to mass spectrometry.

Terroir encompasses environmental (climate, geology, soil and topography), genetic (cultivar and clone) and human factors (oenological and viticultural practices). Climate change brings about shifts in the suitability of a region for the growth of specific grapevine cultivars. This study focused on climatic and fruit parameters (berry size, weight, pH, total acidity (TA) and phenolics) to characterise the terroir effect in Vitis vinifera L. cultivars Chardonnay and Pinot Noir vineyards in the Cape South Coast region (Walker Bay and Elgin).

The last step in winemaking is packaging the wines for market placement, while preserving the quality attained during vinification. Since the 1980s, 2,4,6-trichloroanisole (TCA) has been recognised as an incidental and random contaminant of cork, with its migration into wine thought to contribute to ‘cork taint’. This molecule is not a cork component and little is known about how it is formed on trees. Its formation from the chlorine used to wash the cork stoppers, long suspected, has been excluded by the abandonment of chlorine washing.

The past three decades of terrestrial remote sensing research have delivered unprecedented insights into our fundamental ability to detect, quantify, and differentiate plant disease (Gold 2021). However, much of our fundamental knowledge in this domain has come from studies in non-agricultural systems and until recently, most agricultural studies, when extant, have focused on tree crops where canopy closure and large plot and plant size facilitate stress detection at low spatial resolution. Recent engineering innovations and advancements in constellation architecture design have refined the accuracy and scalability of airborne and spaceborne sensing platforms, enabling us to monitor diverse specialty crops, including grapevine, planted in smaller, spatially varied fields.

A positive role of mannoproteins on wine stability and red wine mouth sensations has been widely described. Commercial mannoproteins are available and some yeast strains are offered with a higher formation of mannoproteins.