An alcoholic beverage is any potable (drinkable) liquid containing ethanol or ethyl alcohol. It may have as little as 0.5% to 95% alcohol by volume depending on the method by which the alcohol is obtained. However, social and economic factors, so also the taxation laws determine what are alcoholic beverages. For example, certain bitters and medicinal compounds contain as much as 40% alcohol; even then they are not considered as alcoholic beverages and are not taxed.However, Alcoholic beverages can be addictive and the state of addiction to ethanol is known as alcoholism.
Fermentation is the process in which sugar is converted into alcohol. It is a chemical reaction of a yeast. Alcohol level of all fermented drink is between 4% to 14%.
French biologist Louis Pasteur (1822-95) explained scientifically the principle of fermentation, which is basic to the making of all alcoholic beverages. When yeast is added to any sugar-containing liquid, it reacts with sugar of the liquid to form the alcohol and CO2. This fundamental process is called fermentation. If this liquid is not protected from air, it is later converted into vinegar.
Thus, fermentation is the breaking of organic substances by enzymes secreted by yeast cells into mainly ethyl alcohol and carbon dioxide gas. This is an exothermic reaction i.e. heat is liberated during this reaction.
Fermented Sugars + yeast enzymes = Alcohol + CO2 + heat
Scientifically describing, the enzymes secreted by yeast cells react with one molecule of sugar (maltose) to produce two molecules of Ethanol and two molecules of carbon dioxide gas. Heat is generated during this reaction.
Carbon dioxide gas is usually allowed to escape. Here, the alcohol (ethanol)- a liquid remains behind in the original liquid, which is then called a fermented alcoholic beverage. These fermented alcoholic beverages are preferably rested, aged, matured and blended before being bottled for sale. Fermented alcoholic beverages have an alcoholic strength of generally 4% to 14% by volume. For example, Wines, Mead, Cider, Perry, Beers, etc.
A point, which is very important, is that alcohol is obtained from ingredients containing sugar. For example, grape juice, apple juice, pear juice, etc. But, it can also be obtained from ingredients like grain, cereals, and potatoes, which have no sugar but have the potential to form sugar i.e. these cereals have a lot of starch present in them. Once the starch is converted into fermentable sugars, mainly maltose, yeast is introduced and fermentation begins.
Another point that requires mention is that certain fermented beverages like beer, sake etc are brewed before they are fermented i.e. the mixture of grist (mashed cereals) and hot water is brewed to extract the flavor, texture, and aroma before they are fermented.
The process of separating one or more liquids by heating the mixture of liquids is called distillation. It involves the sub-processes of evaporation and condensation.
Distillation is the process in which alcohol is separated from the fermented juice by heating it. The principle of distillation is ethyl alcohol vaporizes at a lower temperature (78.5oC) than water vaporizes at 100oC. So, when any fermented liquid is heated to an enclosed vessel (called a still) to a temperature of 78.5oC, water remain in the still and alcohol vaporizes which is channeled off and later condensed to obtain a concentrated alcoholic liquid again. This concentrated alcoholic liquid obtained after distillation is called spirit- a kind of distilled alcoholic beverage.
This distilled alcoholic beverage depending upon the method of distillation (whether pot still or patent still) may be rested, matured, blended and reduced in strength by adding de-ionized water and probably given color enhancement before being bottled for sale. For example, gin, vodka, whiskey, etc. These fermented and distilled alcoholic beverages generally have an alcoholic strength ranging from 37.5% to 57.5% by volume. But, some distilled alcoholic beverages have an alcoholic strength as high as 75% by volume.
The stilling is the process of separating alcohol from water. A still is an apparatus to distil spirits of fermented mash of various cereals, fruits and plants. There are two types of still used for distilling spirits. They are:
The pot still is originated in the Middle Ages and is associated with separate, slow and low-temperature distillations. As a result, the end product contains a good proportion of congeners and spirits obtained by this method have to be matured at least for 2 years by law. But, usually, it is matured longer than that. The entire heavy, highly flavorsome spirits are distilled by this method. For example brandy, malt whiskey, dark rums, tequila and fine calvados, etc.
The pot still is shaped like giant onions and consists of two parts: a still and a worm condenser. The still is made up of copper because it is a good conductor of heat and also resists the effects of acids, which are normally capable of dissolving metals. The copper worm condenser is connected to still by a copper pipe. The worm passes through the jacket of cold water, which speeds of the condensation of alcohol rich vapors. The pot still is time-consuming and costly to operate. It needs to be cooled, cleaned and refilled after each distillation, but it produces spirits of remarkable individuality, quality, and flavor.
The patent still or Coffey still is named after its inventor, Aeneas Coffey- An Irish Chemist. It works on the principle of distillation by steam and produces a continuous flow of high strength alcohol. It uses rectification to make the end product as pure and congener-free as possible. As a result, no maturing period is required by law and the resultant product can be sold immediately after it has been produced.
It is cheaper than pot still method to operate as it is lighter on fuel and doesn’t require the labor intensive tasks of emptying, cleaning and refilling. But it cannot the alcoholic strength of the spirits is low in patent still comparatively to the pot still. The patent still is associated with all the light spirits such as vodka, gin, white or light rum, grain whiskeys, etc.
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