Agronomical assessment of a vine « terroir » map: first results in the « AOC » Minervois region

La mesure de la résistivité électrique des sols est une technique non destructive, spatialement intégrante, utilisée depuis peu en viticulture. L’utilisation d’appareils de mesures performant et de logiciels adaptés permet de traiter les données afin de pouvoir visualiser en deux ou trois dimensions les variations de textures ou d’humidité d’un sol.

Consumers typically prefer wines with floral and fruity aromas over those presenting green-pepper, vegetal or herbaceous notes. Pyrazines have been identified as causatives for herbaceous notes in wines, especially Bordeaux reds. However, pyrazines are not universally responsible for herbaceousness, and several other wine volatile compounds are known to produce distinct vegetal/herbaceous aromas in wines. Specifically, volatile aldehydes elicit sensations of herbaceousness or grassiness and have been described in wines well above their perception thresholds.

Grape Phylloxera (Daktulosphaira vitifoliae Fitch) ordinarily has great difficulty establishing leaf galls on the European Grapevine (VitisviniferaL.). Yet populations of leaf-feeding Phylloxera are increasingly being observed throughout commercial vineyards world-wide. Effective plant protection strategies including quarantine actions are currently missing to fight, grape phylloxera populations in affected vineyards and combat linked negative effects on vines and yield. Contrary to the otherwise mandatory continuous infestation pressure from externally established populations (e.g. from populations developed on rootstock foliage or other interspecific hybrids, these leaf-feeding populations seem to establish themselves annually.

The aging potential of Burgundy chardonnay wines is considered as quality indicator. However, some of them exhibit higher oxidative sensitivity and premature oxidative aging symptoms, which are potentially induced by no-enzymatic oxidation such as Fenton-type reaction (Danilewicz, 2003). This chemical mechanism involves the action of transition metal, native phenolic compounds and oxygen which promote the generation of highly reactive oxygen species (ROS) such as hydroxyl radicals (OH) or 1-hydroxyethyl radicals (1-HER) from oxidation of ethanol. Such mechanism is involved in the radical oxidation occurring during bottle aging. According to Elias et al.,(2009a), the 1-HER is the most abundant radical in forced oxidation treated wines. Consequently, understanding its evolution kinetic in dry white wines is of great importance.

Oxidative stability is a critical factor in maintaining wine quality during its shelf-life. SO₂ is commonly added to wine due to its strong antioxidant activity, although there is a general push to reduce SO₂ use in vinification.