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People said that wine is good for health. So I take a cup (less than 100 mL) of wine every evening. (Yes, wine is cheap where I live.) So to finish a bottle of wine (750 mL), it takes me a week. (Of course I put it in the refrigerator.) I have to say that it doesn't taste good after 3 days (but still OK).

But I don't know if it is not safe to do so. Maybe the wine begins to produce something not good for health after a few days when it is opened. So, my question is: what chemical species are formed after opening a wine bottle, making it go bad? Are they only bad for the taste, or also bad unhealthy?

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As a side note: box wine is very efficient for preserving wine from oxidation and spoilage. While in the past, only bad wine could be found in such packaging, nowadays you can find very decent wine in boxes… –  F'x Nov 18 '12 at 15:16
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up vote 3 down vote accepted

The bad taste left after drinking wine can be attributed a number of agents found in wine, particularly alcoholic wines.

Alcoholic wines typically contain 8-15% ethanol. When ethanol mixes with oxygen in air it gets oxidised, gradually producing acetic acid (vinegar).

Furthermore, the reaction of ethanol with urea (naturally present in wine) to form ethyl carbomate (urethane) can produce a saline, bitter taste, although probably not toxic.

The ethanol in wine is produced through the fermentation of carbohydrates by yeast. This process also results in the production of acetaldehydes which contribute to its complex set of flavours.

Ethanol itself however is tasteless. It is however toxic and a class 1 carinogen according to the International Agency for Research on Cancer (IARC).

When consumed, ethanol is oxidised by alcohol dehydrogenase (ADH) enzymes in the body to produce acetaldehyde, which is 10-30 times more toxic than alcohol and possibly carcinogenic in humans.

Recent scientific research on cancer seems to indicate even low levels of alcohol consumption (1 cup per day) 'increases the risk of cancer of oral cavity and pharynx, esophagus and female breast' Source: http://annonc.oxfordjournals.org/content/early/2012/08/21/annonc.mds337.full

So a bad taste may not be the worst thing alcohol leaves in one's mouth.

With regard to the health effects of alcohol, please refer to the World Health Organisation report which is based on data collected scientifically from around the world over many years.

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sobering answer... –  Richard Terrett Nov 20 '12 at 3:56
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