Learning to homebrew
In order to contain caffeine, beer would have to have it added directly or contain some other ingredient that is naturally caffeinated.
Traditionally, beer is brewed with just water, grain, and hops - none of which contain any caffeine.
First, let's get one thing out of the way.
Of course, caffeinated malt beverages like 4 Loko do exist and they are heavily marketed for their caffeine content.
But what about 'real' beers?