Fate of polyfunctional thiols in Sauternes wines through ageing

Recent papers have revealed the importance of polyfunctional thiols in fresh Sauternes wines (1, 2), but very little is yet known about the fate of such compounds during aging in the bottle. Here it is shown that most polyfunctional thiols with roasted or citrus notes (3-sulfanylpropyl acetate, 2-sulfanylethyl acetate, 3-methyl-3- sulfanylbutanal, and 3-sulfanylheptanal) are degraded within a year upon bottle aging in a cellar. Only 3-sulfanylhexan-1-ol was still found in aged samples at concentrations above its threshold value. Most other key aromas previously found in the fresh noble rot wine are still present in aged samples: varietal aroma (α-terpineol), sotolon, fermentation alcohols (3-methylbutan-1-ol and 2-phenylethanol) and esters (ethyl butyrate, ethyl hexanoate and ethyl isovalerate), carbonyls (transnon- 2-enal and β-damascenone), and wood flavours (guaiacol, vanillin, eugenol, β-methyl-γ-octalactone and furaneol).