Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol - and it is a volatile, flammable, colourless liquid. Ethanol is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a solvent and as a fuel. In more common usage, it is often referred to simply as alcohol or spirits.

The fermentation of sugar into ethanol is one of the earliest organic reactions done by mankind; dried residues on 9,000-year-old pottery found in China imply that Neolithic people consumed alcoholic beverages. The intoxicating effects of ethanol consumption have been known since ancient times. Ethanol has widespread use as a solvent of substances intended for human contact or consumption, including scents, flavourings, colourings, and in medicines.

Most alcoholic beverages can be broadly classified as fermented beverages, beverages made by the action of yeast on sugary food-groups, or distilled beverages, beverages whose preparation involves concentrating the ethanol in fermented beverages by distillation. The ethanol content of a beverage is usually measured in terms of the volume fraction of ethanol in the beverage, expressed either as a percentage or in alcoholic proof units.

Alcohol is one of the four energy sources of the human body along with carbohydrates, fat and protein. If you study how the body proccesses wine, you discover that the liver converts the alcohol into acetate, which the body burns for fuel. The body creates 7 calories of energy per gram of alcohol. Fermented beverages can be broadly classified by the food-group they are fermented from. Beers are made from cereal grains or other starchy materials, wines and ciders from fruit juices, and meads from honey.

Alcoholic beverages are sometimes used in cooking, not only for their inherent flavours but also because the ethanol dissolves hydrophobic flavour compounds, which water cannot.