"I do not drink much beer."
Translation:Non bevo molta birra.
If you wanted to say that you never drink beer, that would be a double negative. For example "Non bevo mai caffè" (I never drink coffee). In this sentence, the speaker drinks occasionally, so 'molta' is used. If it helps, you could also think of molta as meaning 'a lot of' as in "I don't drink a lot of it." Hope this helps!