As mentioned before, the fermentation of sugars derived from grapes, barley, corn, potatoes, molasses, milk or any other source produces a wide variety of chemicals, the major one being ethyl alcohol (ethanol). Minor constituents will be methyl, propyl, butyl and amyl alcohols, aldehydes, ketones, esters and a host of other organic compounds in small amounts. These minor constituents are the congeners and the amount of each will determine the flavour, bouquet and colour of a particular beverage. They are also responsible for unpleasant side-effects such as headaches and hangovers since many of them are very poisonous.
When such a mixture is distilled, the first vapours to come over will be rich in the more volatile components such as methanol and acetone. This first fraction is referred to as the "heads". There is no sharp separation so, long before the heads are completely exhausted, the ethanol begins to appear and could be collected, even though it would be somewhat contaminated with heads. Later, when ethanol production is tapering off, the "tails" begin to emerge. These are the least volatile components of the mixture, the propyl, butyl and amyl alcohols known collectively as "fusel" oils. Thus, in a simple distillation using a pot still there are three main fractions — the heads, the tails, and the middle fraction of mainly ethanol contaminated with a little heads and tails, the amount of each depending on where the cut-off is made.
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Acai, Maqui And Many Other Popular Berries That Will Change Your Life And Health. Berries have been demonstrated to be some of the healthiest foods on the planet. Each month or so it seems fresh research is being brought out and new berries are being exposed and analyzed for their health giving attributes.