Valpolicella chemical pattern of aroma ‘terroir’ evolution during aging

Over the past two decades, climate change has contributed to an increase in sugar content in grape must, and consequently, in the ethanol levels of wines.

Tropical wines have been produced in the São Francisco river Valley thirty years ago, in the Northeast of Brazil. The main grape cultivar used for red tropical wines is ‘Syrah’, but wines have presented fast evolution, if they were made in the first or second semester, due to the high values of pH in grapes and wines and high climate temperatures.

Irrigation is an essential tool for grape production, especially where rainfall does not meet the optimal water requirements needed to achieve yield and quality targets. Increased evaporative demand of grapevines due to changing climate conditions, and a growing awareness for sustainable farming, require the improvement of irrigation techniques to maximize water use efficiency, i.e. using less water to achieve the same yields or the same water but larger yields. In this study, the performance of Cabernet Sauvignon vines was compared under three irrigation techniques: conventional aboveground drip irrigation, subsurface irrigation installed directly under the vine row, and partial rootzone drying in which two subsurface lines were buried in the middle of the two interrow spacings on each side of the vine row with irrigation alternated between the two lines based on soil moisture content.

Mannoproteins are macromolecules found on the surface of yeast cells, composed of hyperbranched polysaccharide negatively charged chains by mannosyl-phosphate groups, fixed to a protein core. during the alcoholic fermentation and aging on lees, these mannoproteins are released from the yeast cell wall and become the main yeast-sourced polysaccharide in wine. due to their techno-functional properties, commercial preparations of mannoproteins can be used as additives to better assure tartaric and protein stability.

Grapevine grafting is a complex process that since the establishment of phylloxera has become mandatory for grapevine. Grafting success in grapevine nurseries considerably varies among years and batches with most variety/rootstock combinations reach a high success rate (between 75% and 90%), but some combinations show lower success rates of around 40-50%. The causes of this variation are unknown, although biotic stresses like those caused by some viral infections have been demonstrated to affect the process. European certification schemes for the vegetative propagation of the vine include five major viruses (Arabis mosaic virus, Grapevine Fanleaf Virus, Grapevine Fleck Virus, and Grapevine-associated Leafroll Virus 1 and 3).