Xylem vessel blockages in grape pedicel growing in tropical climate observed by microtomography

In viticulture, microbial communities – particularly fungi – play a vital role in plant health, disease management, and grape quality.

Must fermentation is a complex process influenced by various factors, especially microbiological activities. The characteristics and quality of the resulting wine are closely linked to the stages that unfold throughout this progression.

Bentonite fining is widely used to prevent protein haze in white wines. Most wineries use laboratory-scale fining trials to define the appropriate amount of bentonite to be used in the cellar. Those pre-tests need to mimic as much as possible the industrial scale fining procedure to determine the exact amount of bentonite necessary for protein stability. Nevertheless it is frequent that, after fining with the recommended amount of bentonite, wines appear still unstable and need an additional fining treatment. It remains a major challenge to understand why the same wine, fined with the same dosage of the same bentonite, achieves stability in the lab, but not in the cellar.

Goriška Brda est la région viticole située le plus à l’ouest de la Slovénie, attenante au Collio d’Italie. Goriška Brda (2020 ha de vignobles) a une longue tradition d’élevage viticole. La proximité de la mer Adriatique (Golfe de Trieste) au sud-ouest et des Alpes Juliennes au nord contribue à un climat caractéristique et unique qui influe sur la croissance et la fertilité de la vigne. La constitution des sols, un climat typique et un relief mouvementé provoquent des différences dans la production du raisin, sa quantité et sa qualité. L’utilisation du zonage ou du microzonage permettraient d’atténuer les influences des facteurs climatiques et du sol sur la production de la vigne ou d’en profiter. Pour évaluer la signification des différents facteurs, nous avons résumé et réuni les modèles de différents auteurs.

During oak wood contact, wine undergoes important modifications that modulate its organoleptic quality and complexity, including its aroma, structure, astringency, bitterness and color. Vescalagin and castalagin are the two main C-glucosidic ellagitannins found in oak wood used for wine aging wood but lyxose/xylose derivatives (grandinin and roburin e) and dimeric forms (roburins a,b, c and d) are also present. The presence of several hydroxyl groups in the ortho-positions at the periphery of the structure of the ellagitannin isomers allows these molecules to undergo oxidation or condensation reactions with other compounds.