sulfide and disulfide, are the compounds of sulfur with hydrogen or metallic elements in which the sulfur atom exists in its most reduced state, that is having gained two electrons from the other element or elements in the compound (see reduction).
Sulfides occur naturally during fermentation. Elemental sulfur residues on the grapes from fungicides can be reduced to hydrogen sulfide. The winemaker can detect this problem easily because hydrogen sulfide has an intense smell of bad eggs. Fortunately, the compound is very volatile and can usually be removed by simple aeration.
