Tools for assessing vine nitrogen status; role of nitrogen uptake in the “terroir” effect

Non-Saccharomyces starter cultures became increasingly popular over the years because of their potential to produce more distinctive and unique wines. The major benefit of the use of Lachancea thermotolerans as a fermentation starter is its ability to produce relevant amounts of lactic acid and reduce alcoholic strength, making it valuable for mitigating negative impacts of climate change on grapes and wine quality. Besides, like any other non-Saccharomyces yeast, L. thermotolerans can significantly affect a whole range of other physico-chemical wine parameters.

La mise en valeur d’un terroir au travers du vin signifie dans un premier temps le respect du cahier des charges de l’A.O.C correspondante. Dans un second temps, elle sous-entend d’être à l’écoute des évolutions scientifiques, techniques et sociétales afin de satisfaire une production plus respectueuse de l’environnement et de la santé des hommes. Les recherches effectuées par l’Unité Vigne et Vin du centre INRA d’Angers ont débouché sur le concept d’UTB, Unité Terroir de Base (R.Morlat). UTB définit une aire de terrain ou le fonctionnement de la vigne est homogène en tous points.

The pinking is a phenomenon that can occur in white wine produced with white grape causing the color change from yellow to red-salmon hue. Even if its appearance is highly variable and dependent to the vintage, the wines from certain grape varieties, such as Sauvignon blanc, Chardonnay, Riesling and Trebbiano di Lugana, have been identified to be more susceptible to the pinking.

Aim:  The aim of this paper is to demonstrate that the meaning of terroir should be regarded as transient. This is because climate, one of the principal components of terroir, is changing with time, and can no longer be assumed to be constant with fluctuations about a mean. This is due to the climate crisis.

In red wines, anthocyanins evolve during the wine-making process and ageing. They react with other compounds (such as vinylphenols, acetaldehyde, pyruvic acid…) to form a stable family of compounds called pyranoanthocyanins. Furthermore, the oxidation process can modify the anthocyanic profile of a red wine. It is also interesting to evaluate the occurrence of the different subclasses of pyranoanthocyanins and to characterize their chemical properties. The first objective of this study is to evaluate the occurrence of the different groups of pyranoanthocyanins in an oxidised Merlot wine by a centrifugal partition chromatography strategy. The second goal is to evaluate their relative impact in red wines from Bordeaux region by measuring their concentrations.