Off-flavours
German: Fehlaromen (Off-Flavours) Also known as: Fehlnoten, Off-Flavour, Weinfehler
Unwanted smell or flavour notes in drinks that point to faults in production, storage or hygiene.
Off-flavours are smell and taste impressions that do not belong in a drink. Examples are vinegar taint, sulphur notes like rotten eggs, light-struck flavour, buttery diacetyl, brett notes from yeasts or mustiness. Causes are faults in fermentation, hygiene, storage or packaging.
In the trade, recognising faults is the basis of quality assurance. Some notes are style-defining in small amounts and are tolerated, such as slight yeast notes, while they disturb at higher concentrations. What counts is always whether the note suits the style of the drink.