Nature, origin and prevention of hydrogen sulphide aroma in wines

Abstract

The nature and origin of ‘hydrogen sulphide’ aroma in young wines is studied and means sought for controlling and preventing its occurrence. The aroma is due to hydrogen sulphide and traces of ethanethiol and is formed from bisulphite and elemental sulphur, but not from sulphur‐amino‐acids. The amount formed from elemental sulphur is inversely proportional to particle size. Vineyard sulphur dusts and sprays can give rise to hydrogen sulphide if applied shortly before harvest. Yeasts differ in their power to produce hydrogen sulphide during fermentation and prevention depends on the use of a strain selected for minimal production. Low pH and high fermentation temperature encourage formation. Wine stored on its yeast can produce hydrogen sulphide from elemental sulphur but not bisulphite. The presence of several metals is deleterious especially with large amounts of sulphur dioxide. Removal is best affected in the early stages of development of the aroma by addition of sulphur dioxide and aeration. The mechanisms of aroma formation are discussed.