Micro-meteorological, compositional and transcriptional study of corvina grape color during ripening

The present work contributes by developing a rapid sensory-directed methodology for the screening and selection of high quality wines with different sensory profiles Therefore, Verdejo and Tempranillo musts were fermented with 50 different yeasts each under controlled laboratory conditions. Resulting samples were firstly categorized according to five levels of quality by a panel of wine professionals (Sáenz-Navajas, Ballester et al. 2013). Higher quality samples were described by flash profiling by a semi-trained panel
(Valentin, Chollet et al. 2012) and most distinctive samples were screened by gas chromatography-olfactometry (GC-O) (López, Aznar et al. 2002).

Champagne regulation allows winegrowers to stock small amounts of still wines in order to compensate vintages’ quality shifts mainly due to climate variations. According to their technical requirements and house style some Champagne producers (commonly named “Champagne houses”) use these stored wines in the blend in order to introduce an element of complexity. These wines possess the particularity of being aged on fine lees in thermo-regulated stainless steel tanks. The Champagne house of Veuve Clicquot Ponsardin has several wines stored this way.

ine nitrogen deficiency can negatively influence the aroma profile and ageing potential of white wines. Canopy management can alter vine microclimate, affect the nitrogen availability and influence the response of leaf senescence. Increasing the nitrogen availability to vines can increase the Yeast Assimilable Nitrogen (YAN) levels in harvested fruit and wine. Studies show that foliar nitrogen and sulphur applications at véraison, on low YAN Sauvignon blanc grapes have an effect on the level of amino acids (Jreij et al. 2009) and on S-containing compounds such as glutathione and thiols (Lacroux et al. 2008), which in turn can influence the formation of major volatiles and the aroma profile of the wine.

Barrel ageing is a crucial step in the wine process because it allows many changes to the wine as enrichment, colour stabilization, clarification and also a slow oxygenation. Effects of the oak barrel have to be known to prevent oxidation of the wine. The type of bung used during ageing is also a parameter to consider. Ageing sweet wines in barrel is a real challenge. These wines may need some oxygen at the beginning of ageing but they should be protected at the end of their maturation, to avoid oxidation.

Inactive dry yeast treatments in the vineyard are a tool used with the aim to improve the concentration and quality of secondary metabolites in grapes, leading to a better differentiation of the wines made from grapes differently treated. In this work, a foliar spraying treatment with yeast derivatives specifically designed to be used with the patent pending application technology of Lallemand Inc. Canada (LalVigne® Mature, Lallemand Inc., Montreal, Canada) was tested on Vitis vinifera L. cv. Barbera and Nebbiolo black winegrapes. The aim was to evaluate the effect of this treatment on the phenolic compounds accumulation, the skin physical-mechanical properties and the related phenolic extractability. Prior to analysis, the berries were sorted by flotation in order to evaluate their distribution by density class, and to determine the skin texture parameters of berries with different sugar contents, thus understanding also the ripening effect.