The colorless and very volatile liquid (ethanal, obsolete ethanal) is the aldehyde of ethanol, The name is often mispronounced, correct is "acetaldehyde". It is a natural component of almost all vegetable matter. The substance is at the alcoholic fermentation with liberation of carbon dioxide as precursor of the final product alcohol educated. At the end of fermentation, the proportion usually decreases very much. In normally small amounts acetaldehyde is present in all wines and in low concentration also has no negative taste effects. It reacts with anthocyanins. catechins and sulfur dioxide, which makes it necessary for the formation of pigments (Dyes) is involved. In the bottle it can be faulty due to oxygen contact, for example cork lead to reaction with oxygen and thus impaired aroma, especially in white wines. Acetaldehyde bind sulfur in the wine, or make this a so-called sulfur-eater,
In the human body, acetaldehyde forms as an intermediate in the degradation of ethanol by the so-called alcohol dehydrogenase (see ADH ). It is for the hangover ( a headache, Nausea) after excessive consumption of alcohol. Studies have suggested a link between the consumption of alcoholic beverages and the increased risk of cancer in the digestive tract. There is an increased formation of oxygen radicals, which damage the membranes of the cells. The cause was identified as the crotonaldehyde resulting from acetaldehyde. In Germany in 2008 over 1,500 spirits examined and high concentrations of acetaldehyde in particular fires. port wine and sherry discovered. The highest levels were found in Chinese and Mexican spirits. The lowest were found in beer (11 ± 9 mg / l) and wine (36 ± 42 mg / l). European food law only includes the limit of 0.5 grams of acetaldehyde per hectolitre of pure alcohol, for all other product groups no limit values are defined. Up to this value are health Impairment excluded. Nevertheless, a reassessment seems necessary.
Acetaldehyde develops a numbing odor in its pure form and, when it comes to large quantities in the wine, causes an unpleasant, sharp-bitter, severe sound, which is already in much smaller quantities than the upper limit for skilled tasters sensory easily recognizable. Acetaldehyde is for the Hangover Symptoms such as headache, nausea and vomiting partly responsible. It is also cause of different taste tones like firn (Altersfirn), as well air taste (Aldehyde clay), which as Sherryton desired result of the special vinification. In pronounced form or with the "wrong wine", like a sherryton with normal white wine, this means one wine faults, When reacting with hydrogen sulfide can be foul-smelling thiols (Mercaptans) arise that the sulfurous off cause. See also a list of similar wine defects below Alterston,