I'd cheerily admit that the type of cheap, unripe brie that appears on tables alongside unwashed green grapes and undrinkable four-quid "claret" at wine and wisdom evenings, the sort with an unyielding dry crust and a thick, chalky middle, is a true horror. I like to leave soft cheeses lying around outside the fridge for at least half a day, longer in winter. Mismanaging a brie is as bad as drinking prosecco that's at central heating temp. Give the brie a squeeze before purchase in order to ensure you have a cheese with potential. The main faults I've found with brie have been too much salt and a bitter finish (the latter can mean the cheese has gone past its best). A refusal to ripen is something I associate more with camemberts. Some supermarket bries are marked "ripening." They usually do ok after a few hours at room temp.