Influence of soil type and changes in soil solution chemistry on vine growth parameters and grape and wine quality in a central coast California vineyard

The production of most red wines that are sold involves an alcoholic fermentation carried out by yeasts of the Saccharomyces genus, and a subsequent fermentation carried out by lactic bacteria of the Oenococus oeni species after the first one is fully completed. However, the traditional process can face complications, which can be more likely in grape juices with high levels of sugar and pH. Because of climate change, these situations are more frequent in the wine industry. The main hazards in those scenarios are halts or delays in the alcoholic fermentation or the growth of unwanted bacteria while the alcoholic fermentation is not done yet and the wine still has residual sugars.

Background: Polyphenols extracted from skins and seeds showed different sensory attributes including astringency and bitterness. In previous studies, it has been demonstrated that extracts obtained either from skins or seeds interact differently with salivary proteins.

Cette communication sera basée sur les résultats d’une étude auprès des consommateurs réalisée par la société G3 pour l’I.N.A.O. sur les attitudes des consommateurs vis à vis des produits de terroir et des A.O.C. et sur un mémoire de DEA soutenu par Monsieur J-C. DURIEUX à l’Université de Paris X Nanterre, consacré aux variables explicatives du comportement d’achat des vins A.O.C.

Pinot noir is an interesting vat variety for the high quality products it provides in the most suitable areas. In France, the most important Pinot Noir growing areas are Burgundy, Champagne, Alsace and the Loire. In Italy, Pinot Noir is grown almost exclusively in the northern regions of Trentino-Alto Adige, Lombardy and Friuli-Venezia Giulia.

Climate change represents a major challenge for the French wine industry. Climatic conditions in French vineyards have already changed and will continue to evolve. One of the notable effects on grapevine is the advancing growing season. The aim of this study is to characterise the evolution of agroclimatic indicators (Huglin index, number of hot days, mean temperature, cumulative rainfall and number of rainy days during the growing season) at French wine-growing regions scale between 1980 and 2019 using gridded data (8 km resolution, SAFRAN) and for the middle of the 21th century (2046-2065) with 21 GCMs statistically debiased and downscaled at 8 km. A set of three phenological models were used to simulate the budburst (BRIN, Smoothed-Utah), flowering, veraison and theoretical maturity (GFV and GSR) stages for two grape varieties (Chardonnay and Cabernet-Sauvignon) over the whole period studied. All the French wine-growing regions show an increase in both temperatures during the growing season and Huglin index. This increase is accompanied by an advance in the simulated flowering (+3 to +9 days), veraison (+6 to +13 days) and theoretical maturity (+6 to +16 days) stages, which are more noticeable in the north-eastern part of France. The climate projections unanimously show, for all the GCMs considered, a clear increase in the Huglin index (+662 to 771 °C.days compared to the 1980-1999 period) and in the number of hot days (+5.6 to 22.6 days) in all the wine regions studied. Regarding rainfall, the expected evolution remains very uncertain due to the heterogeneity of the climates simulated by the 21 models. Only 4 regions out of 21 have a significant decrease in the number of rainy days during the growing season. The two budburst models show a strong divergence in the evolution of this stage with an average difference of 18 days between the two models on all grapevine regions. The theoretical maturity is the most impacted stage with a potential advance between 40 and 23 days according to wine-growing regions.