Originally Posted by Atomic_Wedgy
Nothing will work very well as a heap of oxygen is getting in there. My advice is if its a really nice bottle of beer, dont treat it like that.
Give it the respect it deserves and drink it all in one sitting.
My guess was that this wouldn't be a problem, because once the bottle is open and upright, CO2 coming out of solution would displace the air in the bottle because it is more dense. By the time I stuck the plug in, I figured the space in the bottle above the beer would be mostly CO2 and some N2, with very little O2.
As the CO2 is not very reactive with the flavor compounds in beer, I thought that would be all right. In fact, the bicarbonate formed from the CO2 dissolved in the beer is presumably important to the pH buffering and flavor of the beer. That's why I was hoping for an airtight seal. With wine, the big problem is oxygen reacting with various chemicals and, to a lesser extent I'd think, the evaporation of volatile compounds like esters. If you top up a wine bottle with a heavy, inert gas like xenon, I wouldn't think you'd even have to put any cap on at all for a few days. But with beer, the seal is needed, not only to keep problematic chemicals out, but to keep necessary CO2 in.
CO2 is not very soluble in water (or alcohol), so you need the pressure for it to dissolve or stay dissolved. An uncorked beer, even if kept at cellar temp in a box of completely inert gas and away from light, would soon taste different as its pH increased due to carbonation loss.
Of course this is all besides the point as you are right - I should stop being such a Pu&&y and ingrate and just enjoy the beer while it's in front of me!