[homoeccentricus]

Is there any reliable information of what the real impact is of contact between air and beer after primary fermentation is over? Say, I brew a simple IPA. After primary fermentation I put half of the beer in a fermentation bottle that becomes half full, and the other half in a fermentation bottle that becomes completely full. So in the first bottle  the contact surface between air and beer would be much greater than in the second. Suppose I don't stir or do anything else really stupid, would there be a big difference in taste between the first beer and the second, i.e. would the second beer have a more pronounced oxidized taste?

Asking this because I'm still a novice, and up to now I haven't paid much attention to this issue.

BTW, what a lot of people in Belgium seem to do when they are lagering their beer is  to add a lump of sugar. This would then ferment and create a "CO2 blanket" to protect the beer against oxidation. Does this work or is it a myth?

[Wort-H.O.G.]

is this something you are having issue with? if not wouldn't be too concerned. first-fill your bottles up to top and cap with o2 absorbing caps. as far as lagers, never once have i had any issues with o2 in head space. i warm them up before lagering and that releases enough c02 to do the trick for the cold crash to precipitate yeast out. then i purge a keg with c02 and fill-purging again after sealing.

[Joe Sr.]

IME oxidation leads to darkening and off flavors.

In a sealed fermenter with no disturbance oxidation would occur slowly but could still occur.

[homoeccentricus]

is this something you are having issue with? if not wouldn't be too concerned. first-fill your bottles up to top and cap with o2 absorbing caps. as far as lagers, never once have i had any issues with o2 in head space. i warm them up before lagering and that releases enough c02 to do the trick for the cold crash to precipitate yeast out. then i purge a keg with c02 and fill-purging again after sealing.

your intricate procedure does exactly the opposite of what you suggest: it makes me VERY concerned. 

[Wort-H.O.G.]

is this something you are having issue with? if not wouldn't be too concerned. first-fill your bottles up to top and cap with o2 absorbing caps. as far as lagers, never once have i had any issues with o2 in head space. i warm them up before lagering and that releases enough c02 to do the trick for the cold crash to precipitate yeast out. then i purge a keg with c02 and fill-purging again after sealing.

your intricate procedure does exactly the opposite of what you suggest: it makes me VERY concerned. 

not sure what you mean-explain.

[Wort-H.O.G.]

So unless you have one of those fancy bottling chambers with isobaric filling turret where O2 is displaced –you’re going to expose your beer to O2. Filling the bottles and yeast fermenting sugars during carbonation will pretty much take care of your residual o2 (as good as it’s going to get).

As far as carboy to keg-again there is going to be some surface exposure to O2. Unless you’re sloshing it around or pumping pure O2 into it, its going to be minimal. Purging your keg before filling, and purging after sealed is going to displace O2 in the head space. Not once have I had an oxidation issue, and don’t expect I will. Just my method and my experience.

[homoeccentricus]

Say, I brew a simple IPA. After primary fermentation I put half of the beer in a fermentation bottle that becomes half full, and the other half in a fermentation bottle that becomes completely full. So in the first bottle  the contact surface between air and beer would be much greater than in the second. Suppose I don't stir or do anything else really stupid, would there be a big difference in taste between the first beer and the second, i.e. would the second beer have a more pronounced oxidized taste?

All I want know is: has anyone tried this experiment? If so, what was the outcome?

[morticaixavier]

I've not tried it. I expect that over a significant time you would see a differnce. You mention an IPA and I suspect that with an IPA you would see more of a difference quicker because of all the effects oxidation can have on a beer in my experience the quickest, most common, and most noticable (and unpleasant for that matter) is what it does to hop aroma and flavor.

[Joe Sr.]

All I want know is: has anyone tried this experiment? If so, what was the outcome?

I think you should go ahead and report back.

I've oxidized a beer, not purposely, and it was nasty.  Not looking to do it again.

[Wort-H.O.G.]

i guess inadvertently it has happened exactly like you asked- half full 1 gal jug for starter. result is fully fermented beer that is half full, no airlock, and in 5 days or so tastes horrible from oxidation.