There isn't actually a nice phrase for homebrew, unfortunately. I'm working on an article (on again, off again) about Homebrew as Gaeilge, the best I've come up with is something along the lines of "Baile-ghrúdú", but it's not really all that roll-off-the-tongue-y.
Asides from that, I dunno, stuff like "Grúdaím = I brew" and "ceard-bheoir" = "craft brew" (again, probably no official phrase, but that's as good as any) will be as useful as any. Any phrases in particular you're after just give a shout.