Tequila is a distilled alcoholic drink derived from the fermented agave plant. The general group of alcoholic drinks made from this plant are referred to as mescal, of which tequila is a specific and regulated form.
The Agave is not, as is commonly thought, a cactus, but is actually a large succulent more closely related to lilies.
There are hundreds of species of agave, many of which are radically different from one another. One of the most well-known species is the century plant, often found in gardens throughout the world. Tequila is made from a species of agave called blue agave, or Agave tequilana.
The best tequilas are made solely from agave and are usually labeled as being 100%. Others may mix in some other bulk, such as sugar or corn, to supplement the agave, which is quite expensive. In order to be certified as tequila, however, at least 51% of the material used to make it must be agave.
In Mexico, the most traditional way to drink tequila is neat, without lime and salt. It is popular in some regions to drink fine tequila with a side of sangrita – a sweet, sour, and spicy drink typically made from orange juice, grenadine (or tomato juice), and hot chillies. Equal-sized shots of tequila and sangrita are sipped alternately, without salt or lime.
Outside Mexico, a single shot of tequila is often served with salt and a slice of lime. This is called tequila cruda and is sometimes referred to as "training wheels", "lick-sip-suck", or "lick-shoot-suck" (referring to the way in which the combination of ingredients is imbibed). The drinkers moisten the back of their hands below the index finger (usually by licking) and pour on the salt. Then the salt is licked off the hand, the tequila is drunk, and the fruit slice is quickly bitten.
Though the traditional Mexican shot is tequila by itself, lime is the fruit of choice when a chaser must be used. The salt is believed to lessen the "burn" of the tequila and the sour fruit balances and enhances the flavour.