Polyphenols in kombucha: impact of infusion time on extraction and investigation of their behavior during “fermentation”

Prior to winemaking, organic or mineral nitrogen compound concentrations are usually measured in the vineyard and in grape musts. These indicators facilitate vine cultivation decisions, usually through yield or vigor. During vinification, yeast and bacteria metabolize nitrogen compounds in the musts in order to generate biomass. After fermentation, the microorganisms rerelease a part of this nitrogen as soluble compounds into the wines. Another part remains bound in the lees and can be lost during racking. The must’s natural nitrogen quantities, additional supplements during fermentation, and lees contact management enhance the release of nitrogen compounds to the wines. During ageing these nitrogen compounds – primarily the amino acids – are implicated in the generation of odorous compounds such as heterocycles(1).

Le concept AOC permet, par une délimitation précise, la mise en valeur de terroirs particulièrement adaptés à la viticulture. Seuls les terroirs ainsi identifiés peuvent produire des vins portant le nom de l’AOC. Le nom de cette AOC ne peut être utilisé que pour des vins issus de terroirs compris dans l’aire d’appellation, sous peine de sanctions pénales. La délimitation ainsi opérée participe à la protection du nom de l’AOC. A l’inverse, le terroir délimité n’est pas protégé.

Climate change impacts on both yields and quality have increased over the past decades, with the effects of extreme climate events having the most dramatic and obvious impacts. Increasing length and intensity of heatwaves associated with increased water stress necessitates a reevaluation of climate change responses of grapevine and, ultimately, a reconsideration of vineyard management practices under future conditions. Here we summarize results from a three-year field trial manipulating irrigation prior to and during heatwave events to assess impacts of water application rates on vine health and physiology, berry chemistry, and wine quality. We also highlight potential mitigation strategies for extreme heat, both in terms of water application, as well as other cultural practices that could be widely applicable.

An integrated terroir characterization is currently realized in the French northern vineyard: “Anjou”. The concept of Basic Terroir Unit (B.T.U.) and its associated ground model “Rock, Alteration, Alterite” are used in this characterization. This work is coupled to a viticultural survey, based on parcels.

The 1365 ha of the Genevese vineyard are located at the south-western corner of the Swiss plateau, between 395m and 505 m altitude.