Tequila and mezcal are similar in some ways, but they also have one distinct difference. Both liquors are made from agave. Tequila, however, is restricted to using only blue agave in its production process. Technically tequila is a type of mezcal because mezcal encompasses all liquors made from any type of agave. But unless blue agave is used to produce the liquor, it is not tequila.