Originally Posted by Jacktar
Why does it matter if oxygen gets in? Doesn't oxygen get in when you rack to a secondary?
Not if you do it right. The idea when racking beer, weather to secondary or bottling is to keep it as smooth as possible. Keep the agitation to a minimum to keep oxygen out.
Supposedly, if you aerate your beer
(after or during fermentation) it can give it the flavor of wet cardboard.
Originally Posted by brewt00l
Depends on how aerated the beer was...I've tasted very mild examples of wet cardboard and extreme examples that would be best described as wet cardboard pulled from a NYC restaurant dumpster in mid-July. It's a pretty unmistakable flavor.
That's one of the reasons why you're supposed to siphon your beer as opposed to just dumping it around in various containment vessels.