Tonic water


Tonic water is a carbonated soft drink in which quinine is dissolved. Originally used as a prophylactic against malaria, tonic water usually now has a significantly lower quinine content and is consumed for its distinctive bitter flavor, though it is nowadays also often sweetened. It is often used in mixed drinks, particularly in gin and tonic.

History

Quinine powder is so bitter that British officials stationed in early 19th century India and other tropical posts where medicinal quinine was recommended mixed the powder with soda and sugar, and tonic water was created. The first commercial tonic water was produced in 1858. The mixed drink gin and tonic also originated in British colonial India, when the British mixed their medicinal quinine tonic with gin.
Since 2010, at least four tonic syrups have been available in the US. Consumers add carbonated water to the syrup to make tonic water, allowing drinkers to adjust the flavour intensity.

Quinine content

Medicinal tonic water originally contained only carbonated water and a large amount of quinine. However, most tonic water today contains less quinine and is used mostly for its flavor. As a result of the lower quinine content, it is less bitter, and is also usually sweetened, often with high-fructose corn syrup or sugar. Some manufacturers also produce diet tonic water, which may contain artificial sweeteners such as aspartame. Traditional-style tonic water with little more than quinine and carbonated water is less common but may be preferred by those who desire the bitter flavor.
In the United States, the US Food and Drug Administration limits the quinine content in tonic water to 83 ppm, while the daily therapeutic dose of quinine is in the range of 500–1000 mg, and 10 mg/kg every eight hours for effective malaria prevention. It is often recommended as a relief for leg cramps, but medical research suggests some care is needed in monitoring doses. Because of quinine's risks, the FDA cautions consumers against using "off-label" quinine drugs to treat leg cramps.

Use

Tonic water is often used as a drink mixer for cocktails, especially gin and tonic. Vodka tonic is also popular. Tonic water with lemon or lime flavor added is known as bitter lemon or bitter lime, respectively.

Fluorescence

The quinine in tonic water will fluoresce under ultraviolet light. In fact, the sensitivity of quinine to ultraviolet light is such that it will appear visibly fluorescent in direct sunlight against a dark background.