Monday, 18 May 2009

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Alcohols Main article: alcoholic fermentation One of the harmful effects of wine consumption, due to its ethanol content, is alcoholism. Alcoholic fermentation process is an anaerobic metabolism (without oxygen) allowing the yeast (Saccharomyces cerevissiae) consume the wort sugars to release carbon dioxide and ethyl alcohol (ethanol formula CH3-CH2-OH) that remains in solution the final wine. The concentration of alcohol is often measured as a percentage of total volume. The ethyl alcohol content varies depending on the type of grape and the conditions, for example in table wines is between 7 -14 , in sparkling wines: 11 -13 in the sherry and other fortified wines 16 -18 and in Oporto as well as in dessert wines is usually below 17 . The most common way to determine the alcohol content in wine is to measure the boiling point. The wines also have small amounts of other alcohols such as methanol (CH3OH), are not the direct result of fermentation, but the hidrolizacion of pectins (in the skin of the grapes) through enzymatic action. Because pectin is more on the grape skin, white wines contain much less alcohol methyl red wines. In some cases pre-heat the wort to remove this content to be methyl concentrations below 30 ppm. Reports of the methanol content of wines from around the world indicated concentrations of 60 mg / liter (in a range from 40-120 mg / liter) for white wines and 150 mg / liter (in the range of120-250 mg / liter) for red wines. Despite being the maetanol toxic quantities that have the wine are not entirely evil, as the lethal dose of 340 ml / kg makes an average 70 kg person have to take about two hundred liters. Famosas tears crept into the glasses indicate a high content of glycerin in the wine There...