Originally Posted by Husher
I'm assuming that the yeast is what keeps the beer fresh and aging. if the yeast is sterilized at 2 weeks, the beer will go bad more quickly (beer shop says 4 weeks) without refrigeration. The stuff in my basement now has been there for 4 months at 18 degrees and it's fine. Tell me if I'm wrong, but I'm assuming not if the shop is telling me it WILL go bad without refrigeration.
Beer ages. Some beer is meant to be drunk young, and some beer is meant to age. I've never noticed any appreciable difference between how filtered and unfiltered beers age. I've paid good money for aged, filtered barleywines.
If you're sloppy with your handling, you can start to see some oxidation after four weeks I suppose. But, I don't see much reason to believe that the presence or absence of yeast will impact this significantly. Bottle conditioning beer (in contrast to force carbing it) can scrub some oxygen out, perhaps.
There are a lot of good threads on this board about how aging works. It seems like you're getting some strange information, so it might be worth a read.