INCIDENCE OF VOLATILE SULFUR-COMPOUNDS IN CALIFORNIA WINES - A PRELIMINARY SURVEY

Wines reported to have sulfide-related off-odors were analyzed for vol atile sulfur compounds by headspace gas chromatography using a flame p hotometric detector. Fifty-seven of the 77 wines submitted by 19 winer ies in California had one or more volatile sulfur compounds present at concentrations above threshold levels. Dimethyl sulfide (DMS) was the most widely distributed compound and present at the highest levers. E thanethiol (EtSH) and diethyl disulfide (DEDS) were present in most Ca bernet Sauvignon and Merlot and in white wines made from Pinot noir, w ith a lower incidence in Sauvignon blanc and Chardonnay wines. Methane thiol (MeSH) was only found in nine of 19 Pinot noir wines. In the pre sent study, distinct off-odors resulted from very high levels of EtSH (12 wines), DEDS (6), DMS (5) and MeSH (3). In contrast, 17 of the 77 wines contained volatile sulfur compounds at trace, sub-threshold leve ls, while three wines had none detectable, suggesting that sulfide-lik e odor problems may arise from non-sulfur containing compounds or poss ibly sulfur compounds not detectable by this headspace procedure.