Olfactometry approach to assess odorant compounds of grape spirits used for Port wine production-first results

Vitis vinifera L. derivatives are susceptible to contamination by biological agents (e.g., bacteria, viruses, fungi), and chemical agents (e.g., heavy metals, persistent organic pollutants).

This study investigated if compositional differences between Shiraz and Cabernet Sauvignon grape varieties could influence the production of yeast-derived compounds. This work was based on the analysis of 40 experimental red wines made in triplicate fermentations from grapes harvested from two consecutive vintages in New South Wales (Australia). Grapes were picked at three maturity stages using berry sugar accumulation as physiological indicator, from nine commercial vineyards located in three different climatic regions (temperate, temperate-warm and warm-hot). A range of 30 yeast-derived wine volatiles including esters and alcohols were quantified by HS/SPME-GC/MS. Ammonia, amino-acids and lipids were analysed in the corresponding grapes. The juice total soluble solids (°Brix) in addition to the wine alcohol and residual sugar levels were also measured. The influence of grape maturity on wine ester composition was also variety dependent, particularly for higher alcohol acetate and ethyl ester of branched acids. This study highlights that varietal differences observed in Shiraz and Cabernet Sauvignon wines involve fermentation-derived compounds irrespective of the site (soil, climate, viticultural practices).

The terroir concept is presented as the basis of the A.O.C system, in the french vineyards. The “Anjou terroirs” programme aims at bringing the necessary scientific basisfor a rational and reasoned exploitation of the terroir. lt must lead to finalizing a lighter, more relevant integrated method of characterisation wich could be generally applied.

The global wine production is continuously evolving to meet the new demands and preferences of consumers. in this evolving scenario, it’s important to determine which trends will be short-lived and which will remain over time. The promotion of healthier habits has encouraged consumers to try to find alternatives with low or no alcohol content. The challenge for the industry is to produce an alcohol-free wine that retains the familiar aromas and mouthfeel of traditional wine but without alcohol. Ethanol is the most abundant compound in wine, excluding water.

In the Champagne vineyards, spring frosts are the cause of significant variations in the volume of the harvest which are very penalizing for the trade. This variability is reflected both in time (years without frost alternating with years with severe frosts) and in space. Certain sectors of the vineyard are in fact statistically more susceptible to frost than others, but each year no municipality can consider itself immune to this climatic accident. The objective of the study is precisely to analyze the spatial distribution of frost and to determine its main mechanisms, linked to the topography of the hillsides, their orientation but also to regional meteorological variables.