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

Wines reported to have sulfide-related off-odors were analyzed for volatile sulfur compounds by headspace gas chromatography using a flame photometric detector. Fifty-seven of the 77 wines submitted by 19 wineries 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. Ethanethiol (EtSH) and diethyl disulfide (DEDS) were present in most Cabernet Sauvignon and Merlot and in white wines made from Pinot noir, with a lower incidence in Sauvignon blanc and Chardonnay wines. Methanethiol (MeSH) was only found in nine of 19 Pinot noir wines. In the present 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 levels, while three wines had none detectable, suggesting that sulfide-like odor problems may arise from non-sulfur containing compounds or possibly sulfur compounds not detectable by this headspace procedure.