You gotta go to Belgium for the best beers. I always take the train so I'm not sure what the BRU airport lounges offer, but some of the hotel lounges have good beer. The Brussels Hilton serves draft Leffe in the EL. The HIX in Mechelen has several specialty Belgian beers in the fridge. One free to Platinum members, but it's technically not a lounge. It's been years since I've been to the Hilton Antwerp so I can't say what they have, but it ought to be good.

Regarding the Africa post above, the IC Nairobi always has Tusker and Pilsner in the lounge fridge, both of which are good. I think most of the airline lounges at NBO have the same.

And at least some of the LH SEN lounges in Germany have Franziskaner Hefe-Weisse on tap. MUC for sure.