Originally Posted by DC_Steve
The real question is how the hell are you going on an 8 month vacation. I'm jealous.
Amen to that. Please tell your secret.
But those caps make no sense.
Claiming something absorbs oxygen, Or specifically dioxygen (o2), and NOT carbon dioxide (co2) is physically impossible since co2 contains 02.
So either the manufacturers are making false claims, or they really do absorb o2. Which, if that's the case and they do indeed absorb O2, physics says that they must absorb co2 as well.
Furthermore. The small amount of o2 in the bottle will dissipate into the beer because of the pressure and be used by the yeast.
So, simply, the yeast will absorb more oxygen more effectively than any fancy cap will.