Climate ethnography and wine environmental futures

Prior to winemaking, organic or mineral nitrogen compound concentrations are usually measured in the vineyard and in grape musts. These indicators facilitate vine cultivation decisions, usually through yield or vigor. During vinification, yeast and bacteria metabolize nitrogen compounds in the musts in order to generate biomass. After fermentation, the microorganisms rerelease a part of this nitrogen as soluble compounds into the wines. Another part remains bound in the lees and can be lost during racking. The must’s natural nitrogen quantities, additional supplements during fermentation, and lees contact management enhance the release of nitrogen compounds to the wines. During ageing these nitrogen compounds – primarily the amino acids – are implicated in the generation of odorous compounds such as heterocycles(1).

Botrytis cinerea is a necrotrophic pathogen that causes one of the most serious diseases of the grapevine (Vitis vinifera), grey mold or Botrytis bunch rot. In Champagne, the Botrytis cinerea disease leads to considerable economic losses for winemakers and wines exhibit organoleptic defaults.

Grape flavour management in the vineyard requires knowledge of the derivation of individual flavour and aroma characteristics and the effects that different concentrations and interactions between these compounds have on flavour potential.

Minervois is a vine region where the first detailed soil map was begun 30 years ago. In 2003, a new map was drawn plotting the soil-landscape associations. This map distinguishes 8 large soil units based on geology. The widest (called « marnes ») is the most complex : it is made of 57 sub-units, which leads to a high variability of the vine behaviour on this unit.

AIM Methyl salicylate (MeSA) has been reported as a potentially impactful compound in Verdicchio wines produced in central Italy. Lugana is another white wine produced in the north-east of Italy from a grape locally known as Trebbiano di Soave, sharing a very similar genetic background with Verdicchio. The aims of this study were evaluating MeSA occurrence in Lugana, assessing its aroma impact on white wines aroma and elucidating its biogenesis during vinification. METHODS Fifteen Lugana wines were analysed for methyl salycilate content in comparison with Verdicchio, Pinot grigio and Garganega wines. MeSA impact on white wine aroma was studied by means of triangular test, adding MeSA at different concentrations. Possible routes of MeSA formation by yeast were investigated by means of a high throughput assay in which S. cerevisiae cells were put in contact with precursor such as salicylic acid (esterification) or glycosidic extracts (glycosidase). Sub-fractions of Lugana glycosidic extracts were also obtained by HPLC fractionation, allowing further evaluation of precursors role.