Thiols

Large group of volatile organic sulphur compounds (also alkanethiols, thioalcohols and, as an obsolete trivial term, mercaptans). They belong to the organic acids with a somewhat higher degree of acidity than, for example, alcohols and phenols. They are derivatives of hydrogen sulphide. They are formed during decomposition and rotting processes of organic material, for example during or after the fermentation of grape must from a chemical reaction with ethanol (drinking alcohol) or acetaldehyde. Among other things, this process is favoured by yeast sedimentation, which is common especially in white wines. Thiols are found as flavouring substances mainly in milk, cheese, onions and garlic.

Thiole - Skunk und Johannisbeeren

They have an intense, leek- and herb-like to putrid odour that is often disgusting (several thioalcohols are also found in the glandular secretions of skunks). This is why they are added to industrial natural gas as an odour warning. The type ethanthiol (ethyl mercaptan) causes the wine defect boekser (sulphur boeker). Certain thiols, however, are responsible for the positive cassis, lime and grapefruit aromas in wine that are typical of bouquet varieties. Benzylthiol (toluolthiol, benzyl mercaptan) is the cause of the flint aroma, which is counted among the mineral tones.

Skunk: by Silvia on Pixabay
Currant: by jacqueline macou on Pixabay

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Thiols

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