Originally Posted by tackett
O3 is ozone.
O2 is dioxygen
O is oxygen.
If you remember high school chemistry correctly, then you will know that of the six types of reactions, a synthesis reaction is the one that's easily broken. (Which is what c+o2(2)--->co2 is)
It's impossible to absorb gaseous o2, and leave the co2 untouched.
Well I wouldn't say it's impossible, but I highly doubt a cap can do a differentiation decomposition. There's about as much chance of that as me growing an extra 8" down south.
That must have been an absolutely fascinating science class. Perhaps as taught by an english or geography major.
Oxygen absorbing caps contain a material (likely iron or another metal) held in a resin behind a membrane which is permeable to oxygen, but not to the oxides of whatever material are held in the resin. When wetted the material oxidizes, thus removing oxygen from the beer, drawing it across the membrane.
If you are bottle conditioning anyway, I would think that the yeast would take care of that anyway, although perhaps the caps do it a little more quickly, I'm not sure.
For a short lived beer they wouldn't make a difference but perhaps they can delay staling a little in a beer that's being put up a while. They aren't really expensive anyway, so why not I guess....