Originally Posted by Marcellus
This really doesn't make sense since its that exact same beer either put in a keg or bottle. It shouldn't taste any different if you drink it out of a glass. One possibility is keg beer can be fresher which helps many styles where bottled beer could be rather old. But that's a circumstance of age not the beer actually being better.
The the big exception is bottle conditioned beer is not available in kegs or is different from because they don't add yeast etc...to the kegs like they do in the bottle.
Duvel is a great example of this. Its actually a lower ABV in tap that out of the bottle.
Aside from aging and conditioning that may take place in a bottle actually making the beer better in the bottle there is no reason keg beer should taste better unless its simply fresher.
I bet you could do a blind test and wouldn't know the difference out of glass at the same temp etc....
Shit I just remembered something, carbonation level can be different and most likely will be different out of a keg vs bottle with bottles usually having higher carbonation so you could see a slight difference there.
Additionally, the size of the container can help (or hinder) certain beers, for some reason I don't quite understand. Compare a 12oz. bottle of St. Bernardus 12 with a 750mL bottle; the 750 is noticeably better in aroma and flavor.
So I can see some beers tasting fuller because of the size of the keg.