Putting a wine into a bottle and let it age from months to years has a gambling component which some new findings will reduce. The first finding has to do with the fact that different wines are able to produce -per exactly the same amount of consumed oxygen-, extremely different amounts of oxygen-related carbonyls. Depending on the carbonyl, differences are close to two orders of magnitude. Second; those so diverse carbonyl formation rates are related to wine metal content (iron, copper and manganese) and also, surprisingly, to the wine content on precursor amino acids. The third finding has to do with the fact that at least part of the oxidation-related aldehydes are already present in the wine in the form of bisulfite-complexes, so that part of the increase on the carbonyl levels noted upon wine aging in the bottle, is just the simple consequence of the reversion of the bisulfite complex upon oxidation of sulfite to sulfate. The forth finding has to do with the development of an analytical strategy that makes it possible to measure both odor active forms of hydrogen sulfide and small wine mercaptans and odorless but potentially odor-active forms. Such strategy has revealed that the storage of wine under strict anaerobic conditions creates eventually the conditions �lowering wine redox potential- under which odorless mercaptan species are transformed into odor-active forms. Only in some whites and ros� wines, a slight �de novo� formation of mercaptans has been observed to date, suggesting that in reds, formation of mercaptans is more the consequence of the reduction of some unknown form of metal cation complexed to the previously existent mercaptan than the direct reduction of sulfur itself. All these results are discussed in terms of wine sensory properties.Funded by Spanish MINECO (AGL2010-22355); Partly supported by Nomacorc

New insights into the chemistry involved in aroma development during wine bottle aging: Slow redox processes, metal catalytic reactions, chemical equilibrium shifts and perceptual laws

248th National Meeting (2014)

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