The question is: do we really need to do that? I've never seen reports of oxidation in finished beer that didn't involve splashing or over stirring the beer. Can anyone provide links to reports of oxidation that occurred when the normally recommended precautions for racking and packaging were followed?
For oxidation to occur, you have to get O2 into the beer. O2 will diffuse into still beer given enough time, but the amount of diffusion in half an hour or so will be minuscule. Agitation will cause O2 to diffuse in much faster, and so is to be avoided.
Brew on
Well, the thing is, oxidation IS in most homebrewed beer, to one degree or another and this magnifies with age.
A classic example is a barley wine that is 3-4 years old. Signs of oxidation- sherry notes, prunes, etc- are actually part of the profile. A "big" high alcohol beer can really be nice with those notes, and those come from oxidation.
Most beers aren't drunk when they are that old, as oxidation is NOT a desired part of the profile. So, in a beer that has been well taken care of, and is being drunk before a year old may not show as many signs of oxidation but there well may be some, especially if the beer is stored at room temperature as warmer temperatures accelerate aging and those flavors.
With oxidation, several more subtle flavors occur before the classic "wet cardboard". First, hops and lighter flavors are muted a bit, as the beer starts to show signs of oxidation. In beers using dark/black malt, you may begin to notice a slight metallic taste that wasn't there before, as for some reason black malt tends to get that flavor of oxidation. I'm not sure why, so I"d have to research more into that, but several other noted BJCP judges have commented on that as well.
Then, the beer will actually start to darken a bit in color, say, from a light amber to copper. At that point, the madierization (the beginning of those "sherry" notes) starts and the beer can take on the madiera flavor, or sherry, and all the way up to brandy-like flavors as it worsens. The beer may also start to show signs of staling.
I've judged a lot of competitions as a BJCP judge, and the flaws I see most often are generally related to oxidation. Still, I've never once tasted a beer I would describe as "wet cardboard" or "moldy", the terms people on this forum says.
I've heard MANY people say, "Well, my beer isn't oxidized and I splashed it, etc". That's not true. It may not taste severely oxidized (the classic wet cardboard") but I bet if it was judged by a competent judge that some of the signs mentioned above are in that beer. It's not always unpleasant, especially in the early stages, but there is a note in there that will usually change with time and worsen.
