Sources of volatile sulfur compounds in wine

Undesirable volatile sulfur compounds with aromas, such as boiled or rotten egg, sewage and rubber, can impact negatively on wine sensory attributes. The identity of these molecules is known but knowledge gaps exist about their source and ways to manage them in winemaking. This review focuses on the chemistry of the three main compounds: hydrogen sulfide, methanethiol and dimethylsulfide. Discussion centres on their possible origins and the efficacy of methods currently used to control them during wine production. The role of metals, both in the vineyard and in the winery, in the formation and release of these three volatile sulfur compounds is described. Oxygen management during fermentation and bulk ageing is discussed along with the impact of the bottle closure.