Analysis of mousy off-flavour wines

Dans la région des Coteaux du Layon, en Maine et Loire, l’effet terroir et son déterminisme sont étudiés dans le cadre de la production des vins liquoreux. Ces vins sont le résultat d’une maturité poussée au delà de celle prévue par la nature afin de donner aux baies une teneur en sucre et en matière sèche très forte, pour mieux valoriser ces effets de la surmaturation, les baies sont récoltées selon la méthode des tries successives (Asselin et al, 1996). Ainsi, on ne récolte à chaque passage que les grains ayant atteint le niveau de concentration requis pour obtenir des vins à fort degré d’alcool avec des sucres résiduels.

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According to the last IPCC report, the scale of recent climate changes are unprecedented over many centuries. Each of the last four decades has been successively warmer than any decade since 1850. Projections for the future foresee that temperature could reach +3.3°C to +5.7°C under the most pessimistic scenario. It is also projected that every region will face more concurrent and multiple changes in climatic impact-drivers. The frequency of extreme climate events is also likely to increase, as well as the occurrence of indirect constraints. These evolving climatic conditions are alrealdy affecting and will continue to affect the suitability of traditional wine grape production areas, but also create opportunities in new locations.

This study explored the responses of Chardonnay and Sauvignon blanc grapevine cultivars to water deficit across four years, uncovering their shared patterns and distinctive coping mechanisms. The research was conducted in a commercial vineyard located in Isla de Maipo, Chile. Various characterization approaches were employed including plant water potentials (), gas exchange measurements, shoot vulnerability curves, productivity assessments, and leaf cell water relations. Linear mixed models and sensitivity analyses were performed using various statistical methods to evaluate cultivar responses to water deficit. As the water deficit progressed, both cultivars displayed a parallel reduction in stomatal conductance, leaf turgor, and increased shoot embolism.

Malolactic fermentation (MLF) is a secondary step in the vinification process and it follows alcoholic fermentation (AF) which is predominantly carried out by Saccharomyces cerevisiae. These two processes result in the degradation of metabolites to produce secondary metabolites which also contribute to the final wine flavour and quality. AF results in the production of ethanol and carbon dioxide from sugars and MLF stems from the degradation of L-malic acid (a dicarboxylic acid) to L-lactic acid (a monocarboxylic acid). The latter process results in a smoother texture as the acidity of the wine is reduced by the process, it also adds to the flavour complexity of the wine.