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Alcohol - Реферат

на тему: Alcohol
" 1 Chemistry
" 2 Alcoholic content
" 3 Flavoring
" 4 History
o 4.1 Fermented beverages
o 4.2 Distilled beverages
" 5 Uses
" 6 Legal considerations
" 7 Types of alcoholic beverages
o 7.1 Non-distilled beverages
o 7.2 Distilled beverages
" 8 See also
" 9 References
" 10 External link
Bottles of cacha?a, a Brazilian alcoholic beverage.
Alcoholic beverages are drinks containing ethanol.
Alcoholic beverages have been widely consumed since prehistoric times by people around the world, seeing use as a component of the standard diet, for hygienic or medical reasons, for their relaxant and euphoric effects, for recreational purposes, for artistic inspiration, as aphrodisiacs, and for other reasons. Some have been invested with symbolic or religious significance suggesting the mystical use of alcohol, e.g., by Greco-Roman religion in the ecstatic rituals of Dionysus (also called Bacchus), god of drink and revelry; in the Christian Eucharist; and at the Jewish Passover.
Moderate consumption of alcohol, defined by the U.S. Department of Agriculture and the Dietary Guidelines for Americans as no more than two drinks for men and one drink for women per day, is consistently shown as being beneficial for the heart and circulatory system (the UK equivalent is 3-4 units per day for men and 2-3 units for women). Moderate consumers statistically have fewer heart attacks and strokes, live longer, have lower blood pressure, and generally report better overall health.
However, some people are prone to developing a chemical dependency to alcohol, alcoholism. The results of alcoholism are considered a major health problem in many nations.
Frequent excessive consumption can harmfully interfere with the user's well-being. The neurological effects of alcohol use are often a factor in deadly motor vehicle accidents and fights. People under the influence of alcohol sometimes find themselves in dangerous or compromising situations where they would not be had they remained sober. Operating a motor vehicle or heavy machinery under the influence of alcohol is a serious crime in almost all developed nations.
Some religions-most notably Islam, Latter-day Saints, the Nikaya and most Mahayana schools of Buddhism and some Protestant sects of Fundamentalist Christianity-forbid or discourage the consumption of alcoholic beverages for these and other reasons.
Most governments regulate or restrict the sale and use of alcohol.
The ethanol (CH3CH2OH) in alcoholic beverages is almost always produced by fermentation, which is the metabolism of carbohydrates (usually sugars) by certain species of yeast in the absence of oxygen. The process of culturing yeast under conditions that produce alcohol is referred to as brewing.
It should be noted that in chemistry, alcohol is a general term for any organic compound in which a hydroxyl group (-OH) is bound to a carbon atom, which in turn is bound to other hydrogen and/or carbon atoms. Other alcohols such as propylene glycol and the sugar alcohols may appear in food or beverages regularly, but these alcohols do not make them alcoholic.
It has been suggested that alcoholic impurities, congeners, are the cause of hangovers.
Alcoholic beverages with a concentration of about 50% ethanol or greater (100 proof) are flammable liquids and easily ignited.
Alcoholic content
The concentration of alcohol in an alcoholic beverage may be specified in percent alcohol by volume (ABV), in percentage by weight (sometimes abbreviated w/w for weight for weight), or in proof. The 'proof' measurement roughly corresponds in a 2:1 ratio to percent alcoholic content by volume (e.g. 80 proof = 40% ABV). Common distillation cannot exceed 192 proof because at that point ethanol is an azeotrope with water. Alcohols of this purity are commonly referred to as grain alcohol and are not meant for human consumption, with the notable exception of neutral grain spirits.
Most yeasts cannot grow when the concentration of alcohol is higher than about 18% by volume, so that is a practical limit for the strength of fermented beverages such as wine, beer, and sake. Strains of yeast have been developed that can survive in solutions of up to 25% alcohol by volume, but these were bred for ethanol fuel production, not beverage production. Liquors are produced by distillation of a fermented product, concentrating the alcohol and eliminating some of the by-products. Many wines are fortified wines with additional grain alcohol to achieve higher ABV than is easily reached using fermentation alone.
Ethanol is a moderately good solvent for many "fatty" substances and essential "oils", and thus facilitates the inclusion of several coloring, flavoring, and aromatic compounds to alcoholic beverages, especially to distilled ones. These flavoring ingredients may be naturally present in the starting material, or may be added before fermentation, before distillation, or before bottling the distilled product. Sometimes the flavor is obtained by allowing the beverage to stand for months or years in barrels made of special wood, or in bottles where scented twigs or fruits - or even insects - have been inserted.
A well-stocked bar will include a selection of beers and wines, along with the typical liquors of vodka, rum, gin, tequila, and whisky; each in varying qualities from "well" quality (off brand) to premium quality (name brand) to "top shelf" (usually very expensive, ranging from $50 to several hundred USD per 750 ml bottle). Alcoholic beverages can be combined at the time of serving, sometimes with other ingredients, to create cocktails or mixed drinks. Small servings of pure liquor (shots) are also common, with whisky and tequila being traditionally popular selections.
Fermented beverages
Fermented alcoholic beverages have been known since pre-historical times. Beer was certainly known in Mesopotamia before 4000 BC, as attested to by recipes found on clay tablets and art that shows individuals using straws to drink from large vats and pots.
Wine was consumed in Classical Greece at breakfast or at symposia, and in the 1st century BC it was part of the diet of most Roman citizens. However, both Greeks and Romans generally consumed their wine watered (from 1 parts of wine to 1 part of water, to 1 part of wine to 4 parts of water). The transformation of water into wine at a wedding feast is one of the miracles attributed to Jesus in the New Testament, and his symbolic use of wine in the Last Supper led to it becoming an essential part of the Catholic Eucharist rite.
In spite of the Qur'anic ban (which is somewhat ambiguous and open to interpretation) on alcoholic beverages, wine (usually sold by Christian tavern-keepers) remained fairly popular inIslamic lands over the centuries, as revealed in the verses of Persian mathematician Omar Khayy?m