The origin of the name comes from Arabic and is derived from "guhlu" (powdered galena used to colour eyelids and eyelashes). The Arabs called this "kuhul" and it had the meaning of "most beautiful and finest". The term was then also used for liquids that were considered the essence or "spirit" of a substance. The Arabs are also credited with inventing the distillation of alcohol (for medicinal purposes). From this is derived "Al-kuhul-vini", the finest of wine (wine spirit). The naturalist Theophrastus B. Paracelsus (1493-1541) was the first to use the term "spiritus vini" (wine spirit) for the result of a distillation and eventually the terms wine spirit and alcohol acquired identical meanings. Alcool" was first mentioned in writing in Germany in 1597.
Alcohols are chemical compounds in which one or more hydroxyl groups (hydrogen and oxygen) are directly attached to the carbon. If the molecule contains only one hydroxyl group, it is called monohydric or lower alcohols, if it contains more, it is called polyhydric or higher alcohols (polyols, polyalcohols). Alcohols are organic acids with a very low acidity. In wine, mainly monohydric alcohols occur:
Low-grade alcohols are highly volatile liquids with a typical odour, medium-grade alcohols are soapy-oily and high-grade alcohols are solid, waxy, almost odourless and sweet. Trivalent and higher alcohols are called sugar alcohols (alditols). The most important common characteristic of alcohols is hydrophilicity (water-loving = easily miscible). Ethanol, which is often simply called alcohol, plays a decisive role in wine. It is formed from sugar during alcoholic fermentation with the splitting off of carbon dioxide. As a rule of thumb, 10 grams of sugar per 1,000 grams of grape must yield 0.66% ethanol by volume. However, toxic fusel oils or fusel alcohols (accompanying alcohols) such as methanol also occur in wine and in somewhat larger quantities in spirits as by-products of fermentation in normally small, harmless quantities.
The individual types of alcohol have different boiling points, for example 65 °Celsius for methanol, 78 °Celsius for ethanol and 118 °Celsius for butanol. The significantly lower boiling point of ethanol compared to water enables the distillation of wine (evaporation of the alcohol long before the boiling point of water is reached) and thus the production of high-proof spirits. Likewise, a different boiling point makes it possible to separate the methanol, which is toxic in larger quantities, from the ethanol, which is absolutely necessary.
A balanced alcohol content in wine is an important aspect of winemaking. Alcohol has a strong influence on taste and aroma. Alcoholic beverages have a relatively high nutritional value (fats, carbohydrates). Regarding the other wine ingredients, see under total extract. The calculation of the alcohol level is explained under Blood Alcohol Concentration (BAC). A frequent question is what amount of alcohol is acceptable from a health point of view, or presumably not harmful to health if consumed regularly (see under Health).
See also the keywords alcohol content, alcoholism, alcohol prohibition and health, as well as lists of relevant keywords under alcoholic beverages and alcohol consumption.
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Thorsten Rahn
Restaurantleiter, Sommelier, Weindozent und Autor; Dresden