I see all of this mentioning of concern for the O2 in the headspace of bottling, but I am led to question this. In the 2 weeks that is needed to carbonate, are the yeast not eating sugar, and hence metabolizing? So would it not lead one to believe that they would metabolize that fresh o2, just as they do at pitching time?
Oxygen in headspace
- Thread starter cockybitz
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FirefighterSR2
Well-Known Member
Generally speaking, the only time the yeast use oxygen is during their propagation phase. The 02 is used to create sterols that help strengthen the cell wall, and aid in budding (reproduction). Since bottle conditioning is simply a short period of fermentation (which is an anaerobic process and doesn't require 02) what little 02 is trapped in the head space is generally not used.
Unless you're planning on aging your beer for extended periods of time, or they're subjected to sub-optimal temperatures, the little bit of 02 in the head space shouldn't be much of an issue.
If you're really concerned about it, there are bottle caps that absorb the 02. Just about every homebrew shop carries them. Good luck!
Unless you're planning on aging your beer for extended periods of time, or they're subjected to sub-optimal temperatures, the little bit of 02 in the head space shouldn't be much of an issue.
If you're really concerned about it, there are bottle caps that absorb the 02. Just about every homebrew shop carries them. Good luck!
Hermit
fuddle
From the amount of yeast sediment in the bottom of my bottles, I suspect some propagation. It could because they now have some available oxygen?
We've had a bit of a discussion of it in my bottling tips thread....on the last page, beginning here https://www.homebrewtalk.com/f35/bottling-tips-homebrewer-94812/index9.html#post2269616
It continues til pretty much the last post of the thread.
It continues til pretty much the last post of the thread.
FirefighterSR2
Well-Known Member
Thanks for the link, Revvy
I'm sure there is some small degree of propagation occurring during conditioning. However, I would be willing to bet some beer that the yeast slurry at the bottom of the bottle has more to do with them coming out of suspension than due to propagation.
The easy way to test both theories is to leave a bottle or two unprimed for a couple of weeks and see what the bottom of the bottle looks like. I'll bookmark and report back in a few weeks when I'm at that stage again...
I'm sure there is some small degree of propagation occurring during conditioning. However, I would be willing to bet some beer that the yeast slurry at the bottom of the bottle has more to do with them coming out of suspension than due to propagation.
The easy way to test both theories is to leave a bottle or two unprimed for a couple of weeks and see what the bottom of the bottle looks like. I'll bookmark and report back in a few weeks when I'm at that stage again...
It would be cool if someone answered that...though I too think there might be some reproduction before carbonation....but I dunno.
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