At the most basic level, tequila is a distilled spirit that is made from a plant whose name is the Agave Tequilana Webber; blue variety, more commonly refered to as the blue agave, agave azul or “the plant of the gods” by the Mexicans. Many believe that the blue agave belongs to the cactus family, it does not. In reality it is a succulent, it was once classified in the same family along with Lilys and Aloes, but is now classified in its own family, the Agavacae.
While some of the other varities and species of agave are used to make beverages likie pulque and mezcal, only the blue agave is used to make tequila. Much like champagne which is a sparkling wine, tequila, which is technically a mezcal is a product of a particular place. Not only must it be produced in Mexico, it can only be produced in one of five designated regions. Therefore a beverage made similarily to tequila, but not in one of the prescribed regions, will be called a mezcal and not a tequila. Just how a a beverage made similarily to champagne, but not in a specific region of France must be called a sparkling wine. Therefore every tequila is a mezcal, but not every mezcal is a tequila.
Other basic criteria for an authentic tequila concerns the ingredients used. In order for a product to be considered a tequila, it must contain at least 51 percent fermented juice from the blue agave plant. The other 49 percent can consisit of various sugars that are added during the production.
All of the regulations, including the allowable areas of production, methods of production, restrictions to aging, labelling and other requirements that define and characterise the different types of tequila are laid out in a set of laws called the Norma Oficial. Every bottle of tequila is labelled with a “NOM,” which is a number assigned by the Mexican government that indicates where the tequila was produced.