In España, when you are out and want a beer, all you have to do is say "una cerveza, por favor." A beer, please. There's no need to ask for a menu or check to see what's on tap, as most places offer just one brand. The most choice you typically get is whether you want a pequeño or grande, though that is nothing like the giant mugs that are so popular in the States.
Estrella on tap and tapas in Granada.
Here in El Puerto, what's on tap is normally Cruzcampo, which is brewed in nearby Sevilla. Depending where you are in other parts of Andalucía, you may get a Mahou, Estrella, or an Alhambra. Though some people claim to have favorites, and Cruzcampo is somewhat a source of regional pride, most Spanish beer is generally the same - light, pale, pilsner-style, with very little flavor or body.