Alcoholic Beverages. Simple overview.
All alcoholic beverages are made by fermenting a sugar solution with yeast, a process which converts the sugar to carbon dioxide and ethyl alcohol.
Glucose ethanol Usually one does not start with a pure sugar but with fruit juices for wine, the starch in grains for beer and whisky, the starch in grain or potatoes for vodka, molasses for rum, etc. Over the centuries trial and error have shown that a bewildering variety of sugar sources can be exploited in this manner, even such an unlikely substance as milk being usable because of the sugar lactose it contains. Regardless of the sugar source the alcohol is the same even though the flavour and colour will be different.
In addition to the variations imposed by the source of sugar, the particular strain of yeast and the conditions under which it is used (temperature, nutrients, etc.) also make their contribution to the character of the final product. This is because yeasts produce small quantities of other substances in addition to the main product --- ethyl alcohol. It is no wonder, therefore, that the flavour, colour, aroma and general quality of fermented beverages vary so widely and that a great deal of skill and experience is required in order to produce an acceptable drink.
No alcoholic beverage (with the exception of certain vodkas made in N. America) consists simply of alcohol and water with no other constituent present. If it did it would be colourless, odourless and tasteless. And rather boring to many palates unless you mixed it with something which had a flavour, e.g. vermouth for a martini, tomato juice for a Bloody Mary, orange juice for a Screwdriver and so on. Liqueurs too, normally use vodka as the alcoholic base.
The colour, aroma, and flavour of beers, wines and spirits are due entirely to the other constituents present, the alcohol having nothing to do with it. These other constituents are known collectively as “congeners”. Many of these congeners are relatively harmless but there are always a few produced during fermentation, even during the fermentation of a fine wine, which are actually poisonous. Methanol (rubbing alcohol) is one of them. Fusel oils are another. Surprisingly enough to those of us who have been brought up to believe the opposite, it is the congeners and not the alcohol which are responsible for headaches and hangovers following over-indulgence. You will never get a hangover from drinking vodka, but you will from beer, wine or whisky. More will be said about this interesting and little known fact in the next chapter dealing with health and safety.