| Sumario: | Twelve wines have been stored in anoxia to monitor hydrogen sulfide (H2S) and methanethiol (MeSH) emitted. Emissions were studied for 3 months at 75 °C, 10 months at 50 °C, and 18 months at 35 °C. H2S emissions followed first-order kinetics with half-lives of 0.89 months at 75 °C and (estimated) 24.6 and 160 months at 50 and 35 °C, respectively. Total H2S precursors ([P]0), calculated due to the exhaustion observed at 75 °C, amount to between 1.4 and 2.96 mg/L of H2S. [P]0 correlated with the brine-releasable H2S accumulated by the wines in accelerated reductive aging (AR). MeSH emissions hardly decreased and at 75 °C were between 0.36 and 0.82 mg/L, exceeding the decrease in free methionine (0.26 mg/L on average). MeSH emissions determine MeSH accumulation in AR, far less effectively in red wines, suggesting reactions with polyphenols. MeSH emissions negatively correlated with [P]0, suggesting that these play a key role in regulating redox chemistry during wine aging.
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