Tequila remains a bit of a mystery to many people. At its core, tequila is a spirit distilled from blue agave and can be either barrel aged or not. Technically speaking, tequila is a specific subset of mezcal, since mezcal can be made from up to 30 different types of agave while tequila must be made from blue agave and has to come from certain regions of Mexico. Tequilas come in a few varieties, and you can always tell from the label.
To be called "tequila," it has to come from one of eight regions of Mexico and be made from at least 51.5% blue agave. A true tequila is made from 100% blue agave and will always say so right on the bottle. If it is made from less than that, it is a "mixto" and the remainder is often either distilled from mollassas or is a neutral grain spirit. Mixtos are a great way to add that floral agave sweetness to your bar, and 100% agave tequilas let you add another level of richness and complexity. For 100% blue agave tequilas, you will find them in several varieties: silver/blanco/plata, reposado, anejo, and extra anejo. The silver tequilas are the youngest, unaged options and retain the most raw agave flavor. Reposados are aged in charred oak barrel for at least two months, anejos are aged for at least a year. Extra anejos can be aged for quite a while after that. Just like a whiskey, the longer they age in barrels the more woody character they pick up. Reposados and anejos can be wonderfully complex and offer a deeply layered experience when enjoyed over ice or on their own.
This is also the spot to look for mezcals, which have a smokey, earthy quality. Since the hearts of the aggave plants are fire-roasted before distillation, mezcals are a perfect choice for whiskey and Scotch fans looking to branch out and try something new.