Alternative strategies for eliminating hydrogen sulfide and methanethiol from wine: results and learnings

Abstract

Six different remediation procedures for removing hydrogen sulfide (H2S) and methanethiol (MeSH) from a small selection of wines have been studied. Procedures include three modifications of classical copper fining (two precipitation adjuvants and filtration), purging wine in the reductive state with N2, and oxidation with or without thiol-functionalised polymeric silica (SH-Sil). Free and brine-releasable (BR), H2S, and MeSH contents of wine were determined after the treatments and after accelerated reductive ageing. Results have shown that neither the use of precipitation adjuvants nor filtration improved the results of classical copper fining. Purging wine in the reductive state with N2 can decrease significantly the ability of wine to further accumulate H2S and MeSH, but several cycles are required and success depends on the amounts of precursors present in the wine and on copper levels. Oxidation, regardless of the presence of SH-Sil, was the most efficient treatment to remove “reductive” off-odours in both the short and long term.

Keywords

• sulfur off odours
• wine ageing
• remediation
• quinones
• metal bound
• H₂S