Sulphur off-note
German: Böckser Pronunciation: bök-ser Also known as: Schwefelböckser, Reduktionston
An unpleasant sulphur smell of rotten eggs or rubber, usually caused by yeast stress during fermentation.
A sulphur off-note, called Böckser in German, is a fault smelling of rotten eggs, rubber, cooked cabbage or onion. It stems from sulphur compounds such as hydrogen sulphide and mercaptans, which can form when yeast works under stress, for example with a lack of nutrients.
It occurs mainly in wine but also in beer and fruit brandies. Slight cases can often be softened by aeration or contact with copper. Serious faults remain. When decanting a freshly opened wine the smell may disappear quickly without being a sign of poor quality.
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