Brewed a sweet stout on Saturday and used an airlock instead of a blow off tube which I should have know better not to do but anyway, came home yesterday and the lid was blown off. I figure the top could not have been off more than 12 hrs. The beer seemed to still be fermenting actively. I put a clean/sanitized lid on top and sealed it back up.
Has this ever happened where the beer still turned out good or is the chance for contamination/oxidation too high?