Gold Tequila is unaged silver Tequila that has been colored and flavored with caramel. It is usually a mixto.

Reposado ("rested") Tequila is aged in wooden tanks or casks for a legal minimum period of at least two months, with the better-quality brands spending three to nine months in wood. It can be either 100% agave or mixto. Reposado Tequilas are the best-selling Tequilas in Mexico.

Añejo ("old") Tequila is aged in wooden barrels (usually old Bourbon barrels) for a minimum of 12 months. The best-quality anejos are aged 18 months to three years for mixtos, and up to four years for 100% agaves. Aging Tequila for more than four years is a matter of controversy. Most Tequila producers oppose doing so because they feel that "excessive" oak aging will overwhelm the distinctive earthy and vegetal agave flavor notes.
Mezcal and the Worm The rules and regulations that govern the production and packaging of Tequila do not apply to agave spirits produced outside of the designated Tequila areas in Mexico. Some Mezcal distilleries are very primitive and very small. The best known mezcal come from the southern state of Oaxaca (wuh-HA-kuh), although it is produced in a number of other states. Eight varieties of agave are approved for Mezcal production, but the chief variety used is the espadin agave (agave angustifolia Haw). The famous "worm" that is found in some bottles of Mezcal (con gusano -- "with worm") is actually the larva of one of two moths that live on the agave plant. The reason for adding the worm to the bottle of Mezcal is obscure. But one story, that at least has the appeal of logic to back it up, is that the worm serves as proof of high proof, which is to say that if the worm remains intact in the bottle, the percentage of alcohol in the spirit is high enough to preserve the pickled worm. Consuming the worm, which can be done without harm, has served as a rite of passage for generations of fraternity boys. As a rule, top-quality mezcals do not include a worm in the bottle.