Moonshine is a common name for illicitly-distilled corn whiskey. The term is commonly believed to derive from early English smugglers (called moonrakers because of a 17th century legend) and Appalachian home distillers who often engaged in illegal distillation and distribution of moonshine whiskey clandestinely (i.e., by the light of the moon).
Moonshine is any distilled spirit made in an unlicensed still. As with all distilled spirits, yeast ferments a sugar source to produce ethanol, then the alcohol is extracted through distillation using a still.
Because of its illegal nature, moonshine is rarely aged in barrels like proper whiskey, and it sometimes contains impurities and off flavors, but very rarely other, toxic alcohols such as methanol. The off flavors may come from improper mashing, fermentation and/or distillaton. In popular culture, moonshine is usually presented as being extremely strong and in North America is commonly associated with the Southern United States, Appalachia and Atlantic Canada.
Moonshining is usually done using small-scale stills. Typically, the still is built by the moonshine producer, thus avoiding the legal ramifications of obtaining a still commercially. The most rudimentary moonshine stills are made of 55 gallon drums or sheet metal formed into a tank with a wooden base and head, stove pipe, 55 gallon drum condenser barrel, copper coil or radiator condenser, and a homemade gas burner. However, the pot still is the traditional choice, being popular with early moonshine producers due to its simplicity and ease of construction. More efficient reflux stills are available to the modern moonshiner, either self-built, assembled from a kit, or purchased fully assembled. Lately, do-it-yourself still designs have become widely available on the Internet. "Moonshine" and "Still Making Moonshine" are two documentaries that depict the life of a modern Appalachian moonshiner, the making of a three stage still out of sheets of copper, putting up corn mash, and running whiskey.
Varieties of moonshine are produced throughout the world. A comprehensive list can be found at the link immediately above.
Badly-produced moonshine can be contaminated with toxins, mainly from materials used in construction of the still. Stills employing used automotive radiators as a condenser are particularly dangerous; in some cases, glycol products from antifreeze used in the radiator can appear as well. Radiators used as heaters also may contain lead at the connections to the plumbing. Both glycol and lead are poisonous and potentially deadly.
Although methanol is not produced in toxic amounts by fermentation of sugars from grain starches, contamination is still possible by unscrupulous distillers using cheap methanol to increase the apparent strength of the product. Moonshine can be made both more palatable and less damaging by removing the "foreshot" which contains most of the methanol, if any, from the mash. This is possible because methanol vaporizes at a lower temperature than ethanol. The foreshot also typically contains small amounts of other undesirable compounds such as acetone and various aldehydes.
Any alcohol that is at least 80 US proof (i.e. 40% Alcohol by Volume) is flammable. This is especially true during the distilling process in which vaporized alcohol can accumulate in the air if there is not enough ventilation. This fact is referenced in John Sturges' The Great Escape: to celebrate the Fourth of July, Virgil Hilts and two other Americans distil moonshine from potato skins. While dispensing the drink, Hilts advises the other POWs not to smoke while or after drinking it.
Occasionally moonshine is mixed with flavoring agents or compounds intended to increase the apparent alcohol content, such as methanol. Sometimes, whether intentional or not, this results in a toxic mixture. Results may be capable of causing blindness or death. While poisoning incidents are rare, particularly in developed nations, together with the lack of regulation of moonshine production, they are cause for concern about the safety of moonshine.
In the past moonshine has been mixed with beading oil or lye to fool people into believing that it is of a higher proof. This is because when shaken, bubbles form on the surface relative to the alcoholic strength (known as "the bead"). Large bubbles with a short duration indicate higher proof.
Flavoring Mixtures might consist of fruits, or even bark. The mash may be cooked through birch bark to achieve a mint-like flavor. The product might be cooked through a screen of fruit to achieve a fruit-like flavor. Fruits may be added to the liquor as a flavor additive; however, the resulting mixture may not be of strong flavor.
A common "folk" quality test for moonshine was to pour a small quantity of it into a metal spoon and set it alight, the theory being that safe distillate burns with a blue flame, but tainted distillate burns with a yellow flame. Practitioners of this simple test sometimes held that if a radiator coil had been used as a condenser there would be lead in the alcohol, which would give a reddish flame. This led to the phrase: "Lead burns red and makes you dead." While the flame test shows the presence of lead and fusel oils, it does not reveal the presence of methanol, which also burns blue.
Another test used for moonshine is to "proof". A small amount of gun powder is poured in a dish with the moonshine. It is ignited and if the mixture starts to flame it is "proofed." In other words if it lights then it contains a good amount of alcohol, but if it does not flame the moonshine has been diluted. Note that this only proves the alcohol to be at least 57.15% ABV.