Its been awhile since this thread had a post, but I was wondering about aging beer in a keg while NOT hooked up to CO2 or in the fridge... has anyone successfully done this?/QUOTE]
I have recently batch primed a brew, racked to keg and allowed it to condition for 2 weeks. After those two weeks the keg had plenty of pressure in it, and the beer did carb. In fact, too much pressure because I applied bottle batch priming amounts to the keg.
So I think the keg did seal fairly well, without any external co2. For my next batch I plan to condition in the keg, but then rack that beer to some growlers, such that the keg sediment is left behind. Chances for oxidation yes, but I think no different than picking up growler from draft at a brewpub.