Ancient and recent construction of Terroirs

The wine industry currently relies on a limited number of grapevine cultivars, comprised of numerous clones with slight differences in their viticultural, oenological, or stress-tolerance traits.

In Washington State, the majority of winegrape (Vitis vinifera) vineyards are planted to their own roots. This practice is possible due to the lack of established phylloxera populations, and is preferred due to the ease of retraining after damaging winter cold events. However, own-rooted V. vinifera is generally susceptible to most plant parasitic nematodes that attack grape. In Washington State, management of nematodes is dominated by preplant soil fumigation. One practice that may mitigate economic loss due to nematodes is the adoption of nematode-“resistant” rootstocks.

Dans le cadre de recherches sur la mise en évidence et le déterminisme d’un «effet terroir »un réseau de parcelles du cépage Cabernet Franc greffé sur S04, a été suivi de 1979 à 1990 en Val de Loire (A.O.C. Saumur-Champigny, Chinon et Bourgueil). Des analyses chimiques (N,P, K, Ca, Mg, Fe, Mn, Zn) ont été réalisées sur le sol, les feuilles au stade véraison, les moûts en cours de maturation et à la vendange et enfin sur le vin, pour 18 sites (répartis dans 12unités terroirs de base) et 7 millésimes différents.

The impact of toasting process to produce aroma from oak wood intrinsic composition is well documented. It is admitted that such complexity contribute to the wine quality after barrel ageing. Despite our knowledge on the molecular identification of aroma impact compounds of oak wood, little research have been carried out, on a sensory level, on the aroma diversity of toasted oak wood.

Molecular markers of wine oxydation, such as sotolon or Strecker’s aldehydes that induce respectively nut or curry and boiled vegetables or wilted rose odors, can be percieved as a default by consumers. These volatile compounds are especially formed during the premature aging of wine, but it is likely that several contributing compounds are still unknown as is their combined contribution. This study was carried out to identify the markers of oxydation in Chardonnay wine by Gas Chromatography Olfactometry (GC-O) and to study the impact of these markers on the complex wine aromatic buffer using the Olfactoscan approach.A Chardonnay wine (2018-vintage), taken after malolactic fermentation without sulphites addition, was submitted to an artificial oxidation to simulate more or less prononced premature oxidation. Volatile compounds were extracted by Solid-Phase Extraction (SPE) and analysed by GC-O with a panel of 13 trained subjects. The same extract was also submitted to a second analysis based on the Olfactoscan technique, which allowed to evaluate the impact of each volatile compounds on the complex aromatic buffer of a non-oxidized wine delivered as background odor. Preliminary results revealed three types of behavior. On the one hand, several odor zones appeared only with the background odour, suggesting a synergy effect induced by the compounds in the aromatic buffer. Conversely, odor-active compounds could not be perceived within the background odor suggesting a masking effect. Finally several compounds were found to contribute as key odorants for wine oxydation once mixed with the aromatic buffer. These compounds are still to be identified using complementary techniques.