There's no right or wrong answer here and you should feel free to go with your preference or whatever is in your drinks cabinet. However, as a general rule expect the following from your tequila: Unaged tequila (tequila blanco) can taste citrusy, vegetal, grassy and even herbal. It can taste relatively harsh but works well in long drinks such as this Mexican mule. Aged tequila (tequila reposado) can taste a little spicy and also smoother & richer than tequila blanco.