Soda Water et al.

Soda water. Tonic water. Club soda. Seltzer. Sparkling water. What the hell? There's a lot confusion out there about the differences between the carbonated water mixers, so let's clear things up a bit.

The most basic of the above is simply water containing dissolved carbon dioxide. This is known as sparkling water, soda water, or seltzer water, and was originally produced naturally deep underground where geologic pressure forced CO2 into solution in subterranean water deposits. Today, naturally carbonated water is usually referred to as sparkling water, while soda water and seltzer commonly refer to water that has been carbonated by other means.

Club soda is simply soda water that has a small amount of salts added to it for additional flavoring. Because of this extra flavor, it is my carbonated water of choice for mixed drinks though it's rarely available at modern bars -- the carbonated water found on bar guns is simply tap water that has gone through a mechanical carbonator with nothing else added. Naturally sparkling water with a high mineral content can be used in place of club soda, though it may be more lightly carbonated.

Tonic water has quinine added to it, and a much more interesting story behind it. Quinine is a tropical drug that is highly toxic in large doses, and like many natural toxins has a bitter flavor. In the small quantities found in tonic it is harmless, but still lends a bitter hint to the drink. On the theory that the drug could also kill certain diseases, when the British navy encountered malaria they issued a "health tonic" comprised of quinine and seltzer to combat the illness. To make the bitter concoction more palatable, they would add a measure of their national spirit, gin, to the mix and often squeeze in a piece of the local tropical citrus fruit as well. And the gin and tonic was born, complete with its ubiquitous wedge of lime.

So what are you drinking in most bars? Soda water and tonic. And no, drinking G&T's won't cure malaria.