Spirits A to Z
What Are Spirits?
Alcohol, in its basic meaning, is a hydroxyl compound such as ethanol or methanol. Fermentation is the process by which an organic substance (usually a sugar) is converted by a single-celled microorganism such as yeast into alcohol. A spirit is distilled alcohol. Spirits distillation is the process of heating a fermented liquid, evaporating off the alcohol as vapor, and thencondensing it back into liquid form.
How Are Spirits Made?
Spirits can be made from any organic substance that can be fermented to create alcohol. Most alcoholic beverages are made by fermenting fruit or grain-based solutions. A still extracts alcohol from a fermented liquid by boiling it and then condensing the alcohol vapors, which evaporate from the boiling liquid at a lower temperature than water. For example, an 8% alcohol by volume (ABV) wine or beer distills into a 20% ABV distillate when it is run through a typical simple pot still. The alcohol content can be further increased by additional redistillations that further concentrate the alcohol and reduce the total volume of liquid.
The first and most basic type of still is the pot still, which is an enclosed vessel (the kettle or "pot") that narrows into a tube at the top to collect alcohol vapor that evaporates when the fermented contents are boiled. The tube bends downward off the top of the pot and runs through a bath of cold water. This causes the alcohol vapor to condense back into liquid and drain into a container at the end of the tube. Most pot stills are made from copper. They are considered "inefficient" in that they carry over a percentage of water and chemical compound vapors along with the alcohol vapor. This "inefficiency" can be considered an advantage when producing spirits such as brandy and whiskey that have distinctive flavors.
The column or continuous still has two enclosed copper or stainless steel columns. The fermented liquid is slowly fed down into the top of the first column while steam is sent up from the bottom. The rising steam strips the alcohol from the descending liquid and carries it over into the second column where it is recirculated and concentrated to the desired percentage of alcohol. Column stills are more "efficient" than pot stills in that they extract a higher concentration of alcohol. They are favored for neutral-flavored spirits such as vodka and white rum and also for industrial alcohol.
How Are Spirits Measured?
Spirits are measured by alcohol content. Different scales are used in different countries. Most countries use alcohol by volume (ABV), also known as the Gay-Lussac system, which expresses alcohol content as a percentage of the total liquid volume of the beverage. A 40% ABV spirit contains 40% alcohol. In the United States, the proof scale of measurement is used, with the proof of a spirit being double the ABV. Thus a 40% ABV spirit is 80 proof. A degree symbol is customarily used when expressing proof.
How Are Spirits Classified?
Generally speaking, spirits are classified by the fermented material that they are distilled from. Whiskies, Vodka, Gin and most types of Schnapps are made by distilling a kind of beer made from grain. Brandy is made from fermented grape juice, and Fruit Brandy is made from other fruits. Rum and Cane Spirits derive from fermented sugar cane juice or molasses. Tequila and Mezcal come from the fermented pulp of the agave plant. Fortified wines are hybrid beverages in that they are a blend of fermented wine and distilled spirits (usually Brandy).