Formation and Release of H2S, Methanethiol, and Dimethylsulfide during the Anoxic Storage of Wines at Room Temperature

A total of 21 different wines (13 reds, 5 whites, and 3 roses) were kept at 25 degrees C in anoxia for 379 days. Free and total forms of H2S and methanethiol (MeSH) and dimethylsulfide (DMS) were measured initially and after 117, 221, and 379 days of storage. Levels of free H2S, free and total MeSH, and DMS continuously increased during storage, While levels of total H2S remained essentially unchanged. Average increases of free H2S amount to 6.2 mu g/L (from 1.1 to 12.9 mu g/L), those of free MeSH to 1.6 mu g/L (from 0.7 to 3.5 mu g/L), and those of total MeSH to 1.9 mu g/L (from 1.1 to 3.0 mu g/L), whereas those of DMS were 27.8 mu g/L (from 11 to 69 mu g/L). The fraction of H2S under free forms significantly increased, suggesting that release is a major factor explaining H2S increases. All increases can be satisfactorily predicted from data obtained at 50 degrees C.