A type or brand of beer that has been retired or gone out of production for one reason or another and then makes a come back.
"Why can't I buy Mackeson XXX Stout?
"It's been out of production for a few years while the brewery has been changing hands. Basically, the brew is dead until they decide to relaunch it."
"Man, I'm jonesin'
for some Mack; I can't wait till it comes back as a zombrewie!"