It's got to be something that I'm doing unless Tesco in Dun Laoghaire and Obrien's in Dun Laoghaire get their Brooklyn from the same place (then it could be the distributor...).
Usually we pickup a 6 pack at one of the afore mentioned places, and then store it in the top shelf of the fridge on its side. (Usually the beer has been sitting for 1 or 2 days before the first one gets cracked open.)
Sometimes I get a pretty quick gush, sometimes it's fairly slow; but 3 or 4 of the bottles out of about 4 different 6 packs over several months have done it now. -This doesn't generally happen with other beers...
Adam