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Limiting oxidation: effect of purging headspace O2 in a bottle conditioned IPA

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SwedishBrew

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I guess most important is not to shake the bottle atleast, I have been brewing for just a year and it kinds of boggles met that on all this instruction, people claim to shake the bottle to mix the sugar solution. This has literally ruined 5 - 6 batches. I do put the caps in a no-rinse solution just before cap it on the bottles, so it all works out fine :)
 

Miraculix

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How can shaking ruin the batches? The O2 will get from the headspace air into the beer with time with or without shaking. The difference is, when shaking at the beginning, there might be a chance that the active yeast will still absorb it, as long as there is priming sugar in the solution.

Or does the anti oxygen cap take out the oxygen from the air in the headspace over time?
 

SwedishBrew

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How can shaking ruin the batches? The O2 will get from the headspace air into the beer with time with or without shaking. The difference is, when shaking at the beginning, there might be a chance that the active yeast will still absorb it, as long as there is priming sugar in the solution.

Or does the anti oxygen cap take out the oxygen from the air in the headspace over time?
CO2 have a higher density than O2, thus it would act as a layer over the beer in the bottle. Of course, while bottling, you will mix a bit of air into the beer while filling, but hopefully not so much (depends on how careful you are). Newly produced CO2 from the fermentation in the bottle will then push the oxygen to the top of the bottle and away from the beer. If you have the oxygen-absorbing caps, it will then absorb it.

Spontaneous diffusion will always occur, so a bit of O2 will, of course, enter the beer but it actually takes a while for gases to dissolve into the liquid if you don't force it. That's why it's important to not shake it.

You can see the difference in this video, where the guy does the experiment. I tried it myself and there is a vast difference in taste. As he says, the oxygen you shake down in the bottle have to much time to ruin the beer, before the yeast can take care of it.

 

Miraculix

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Please have a look at the gas law, this higher density/lower density layer forming thing does not really work this way with gases. They will always mix. I think yooper described it quite well with the example recently, that we would otherwise all die because of the co2 in the atmosphere forming a layer on the ground.

However, O2 in the headspace really seems to be a big driver for oxidation, there is another thread here about purging the headspace and the effect it has and it was quite obvious that with the purged headspace the beer was oxidizing much less then with the normal air headspace. Funnily enough, this applied to beer that was bottled really carefully as well as to beer that was bottled very splashy. The end result was the same, purged headspace, no oxidation, air headspace and it was oxidised. So if the caps really work well and absorb the oxygen from the headspace, it should make a huge difference. Not shaking the beer at the beginning of bottle conditioning not so much, as the yeast would absorb the oxygen anyway during fermentation of the priming sugar.
 

Vale71

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CO2 have a higher density than O2, thus it would act as a layer over the beer in the bottle. Of course, while bottling, you will mix a bit of air into the beer while filling, but hopefully not so much (depends on how careful you are). Newly produced CO2 from the fermentation in the bottle will then push the oxygen to the top of the bottle and away from the beer.
Could we please do away with this nonsense once and for all?
Maybe the mods can put a sticky in all subforums "Gases mix readily, they do not float. Deal with it." ;)
 
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While flipping or shaking after capping is completely unnecessary IMO (besides if you need to wet the O2-absorbing caps, as I learned here), I too do not think that this would be such a big driver of oxidation in bottle conditioned beers IF you can count on active yeast at bottling.

It could probably worsen the problem if the yeast ist not active (i.e. bottling cold beer after a cold crash).
In such a scenario you would further encourage O2 dissolution into beer while yeast is not yet able to metabolize it.

Ultimately O2 in the headspace will enter the beer no matter if you shake it or not.
 

SwedishBrew

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Could we please do away with this nonsense once and for all?
Maybe the mods can put a sticky in all subforums "Gases mix readily, they do not float. Deal with it." ;)
Maybe you should consider that's not the issue here. It's forcing the air into the beer :D And sure, gases mix due to the diffusion process, but perfectly? Instantaneous? Do they diffuse equally into the beer? Does all gases get absorb even?
 
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SwedishBrew

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Please have a look at the gas law, this higher density/lower density layer forming thing does not really work this way with gases. They will always mix. I think yooper described it quite well with the example recently, that we would otherwise all die because of the co2 in the atmosphere forming a layer on the ground.

However, O2 in the headspace really seems to be a big driver for oxidation, there is another thread here about purging the headspace and the effect it has and it was quite obvious that with the purged headspace the beer was oxidizing much less then with the normal air headspace. Funnily enough, this applied to beer that was bottled really carefully as well as to beer that was bottled very splashy. The end result was the same, purged headspace, no oxidation, air headspace and it was oxidised. So if the caps really work well and absorb the oxygen from the headspace, it should make a huge difference. Not shaking the beer at the beginning of bottle conditioning not so much, as the yeast would absorb the oxygen anyway during fermentation of the priming sugar.
Well, the atmosphere is an open system with temperature and pressure changes happening all the time thus it diffuses all over the place and gets mixed. A sealed off bottle is a closed system where eventually the gases reach a steady state. Yes there is mixture, but CO2 is still heavier than O2, thus more likely to diffuse into the beer. I could be wrong, but I can't see why wine for example would hold longer in bottle compare to when you open it. Cause then it would just get oxidized no matter if you opened it or not.

I also did the experiment he showed in the homebrew network and it was a significant difference. Can't explain that one otherwise.
 
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Vale71

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I could be wrong, but I can't see why wine for example would hold longer in bottle compare to when you open it. Cause then it would just get oxidized no matter if you opened it or not.
You're forgetting the massive amounts of sulfites that wineries add to their product in order to stabilize it.

With your posts you've clearly shown that you have littlo to no idea of the processes involved in beer oxidation, I respectfully suggest you take that into consideration and maybe try and learn something instead of just posting misinformation.
 

SwedishBrew

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You're forgetting the massive amounts of sulfites that wineries add to their product in order to stabilize it.

With your posts you've clearly shown that you have littl to no idea of the processes involved in beer oxidation, I respectfully suggest you take that into consideration and maybe try and learn something instead of just posting misinformation.
Ok Mr Oxidation, then an open bottle of wine has the same shelf life as an unopened? All those sulfites? So no difference in natural diffusion vs forced diffusion? I honestly want to know :D

You should also have mentioned that wine usually are purge as well. Even apply nitrogen to dissolve O2. But obviously it gets preserved cause it's just a very small amount O2 that leaks in. It's all due to proportions and limiting the exposure to air as much as possible, which is my point exactly.

But what's your issue btw? I say that I get better result with not shaking the bottles after capping. I believe it's due to O2 not get violently forced down into the liquid and CO2 is heavier so it give protection for the beer/gas interface. Is that misinformation?

If I get your point right. CO2 + O2 is a perfect mixture, all O2 gets absorbed into the beer, thus it makes no difference what you do beyond that point? I may have little to no idea of beer oxidation, but you don't really seem to shine either.
 
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Vale71

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But what's your issue btw? I say that I get better result with not shaking the bottles after capping. I believe it's due to O2 not get violently forced down into the liquid and CO2 is heavier so it give protection for the beer/gas interface. Is that misinformation?
Yes it is.

If I get your point right. CO2 + O2 is a perfect mixture, all O2 gets absorbed into the beer, thus it makes no difference what you do beyond that point? I may have little to no idea of beer oxidation, but you don't really seem to shine either.
Right again.
 

VikeMan

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A sealed off bottle is a closed system where eventually the gases reach a steady state.
True to an extent. But O2 that dissolves is subsequently used in oxidative reactions, which decreases the dissolved O2, thus causing more O2 to dissolve into the beer from the headspace. IOW, the "steady state" equilibrium (for O2) keeps shifting.

Yes there is mixture, but CO2 is still heavier than O2, thus more likely to diffuse into the beer.
No. The CO2 will dissolve into the beer until its own equilibrium is reached. The O2 will dissolve into the beer until its own (temporary) equilibrium is reached. These equilibriums are independent of each other.

I could be wrong, but I can't see why wine for example would hold longer in bottle compare to when you open it. Cause then it would just get oxidized no matter if you opened it or not.
When you open a bottle of wine, the O2 in the atmosphere, which is at a higher concentration than in the wine bottle's headspace, diffuses into the headspace, seeking equilibrium. This increased headspace O2 then seeks equilibrium with the O2 dissolved in the wine. So, more O2 gets into the wine, causing more oxidation. There's no mystery here.
 

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True to an extent. But O2 that dissolves is subsequently used in oxidative reactions, which decreases the dissolved O2, thus causing more O2 to dissolve into the beer from the headspace. IOW, the "steady state" equilibrium (for O2) keeps shifting.



No. The CO2 will dissolve into the beer until its own equilibrium is reached. The O2 will dissolve into the beer until its own (temporary) equilibrium is reached. These equilibriums are independent of each other.



When you open a bottle of wine, the O2 in the atmosphere, which is at a higher concentration than in the wine bottle's headspace, diffuses into the headspace, seeking equilibrium. This increased headspace O2 then seeks equilibrium with the O2 dissolved in the wine. So, more O2 gets into the wine, causing more oxidation. There's no mystery here.
Very good explanation, thanks.
 

SwedishBrew

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True to an extent. But O2 that dissolves is subsequently used in oxidative reactions, which decreases the dissolved O2, thus causing more O2 to dissolve into the beer from the headspace. IOW, the "steady state" equilibrium (for O2) keeps shifting.



No. The CO2 will dissolve into the beer until its own equilibrium is reached. The O2 will dissolve into the beer until its own (temporary) equilibrium is reached. These equilibriums are independent of each other.



When you open a bottle of wine, the O2 in the atmosphere, which is at a higher concentration than in the wine bottle's headspace, diffuses into the headspace, seeking equilibrium. This increased headspace O2 then seeks equilibrium with the O2 dissolved in the wine. So, more O2 gets into the wine, causing more oxidation. There's no mystery here.
I would think that CO2 in the mixture had more partial pressure, the more as the time goes. Thus more likely to dissolve, didn't know they diffuse independently, I thought liquid had a total gas saturation.

What do you think of shaking the bottle, any impact? I would believe that the amount of oxygen would dissolve ten times, or so, faster than if you don't shake. Then speed up this oxidation process of beta and alpha acids and what not.
 

VikeMan

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What do you think of shaking the bottle, any impact? I would believe that the amount of oxygen would dissolve ten times, or so, faster than if you don't shake. Then speed up this oxidation process of beta and alpha acids and what not.
Shaking will help reach (temporary) equilibrium a little faster, making O2 available for oxidative reactions a little sooner. Not more, just a little sooner. But will it ultimately increase the potential for oxidative reactions? I doubt it.
 

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Shaking will help reach (temporary) equilibrium a little faster, making O2 available for oxidative reactions a little sooner. Not more, just a little sooner. But will it ultimately increase the potential for oxidative reactions? I doubt it.
So I don't bottle anymore except for competitions, so I really don't "have a dog in this fight". But for my edification on the question, for those rare occasions when I do bottle, does it help to 'wet' the O2 absorbing caps, as long as I don't shake the bottle? (serious Q)
 

SwedishBrew

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Shaking will help reach (temporary) equilibrium a little faster, making O2 available for oxidative reactions a little sooner. Not more, just a little sooner. But will it ultimately increase the potential for oxidative reactions? I doubt it.
But shouldn't it? Cause if you don't shake, you start with one gradient in the top (small surface also), as air starts to get absorbed into the liquid. Then that concentration gradient of oxygen in the top of the beer would make the oxygen diffuse down into the bottom of the bottle, this much be so much slower than just shake it an introduce are all around in the bottom and basically make the entirity of the liquid be one big interface of beer to oxygen?
 

VikeMan

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But time it takes for that to happen?
Less time than it will take a normal human to drink a 5 gallon batch of beer. My swag would be a few days. A couple weeks at most.
 

SwedishBrew

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Can't really explain this experiment then. The two bottles to the left is shaken after capping, while the one to the right is not shaken. They were capped more than a month when I took this photo. The two to the left tasted awful, like somehow sour-bitter, the one to the right just perfect, didn't even feel a touch of oxidization. It was a very hazy NEIPA style and it was still very hoppy in taste.
 

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Can't really explain this experiment then. The two bottles to the left is shaken after capping, while the one to the right is not shaken. They were capped more than a month when I took this photo. The two to the left tasted awful, like somehow sour-bitter, the one to the right just perfect, didn't even feel a touch of oxidization. It was a very hazy NEIPA style and it was still very hoppy in taste.
The first bottle has a significantly larger headspace than the other two. This alone could have increased oxidation.
The third bottle seems larger than the others, especially it seems much larger than the second one. So less headspace-to-beer ratio?
(I'm speculating a bit here ;-))

Aside from that: Did you cold crash? Did you bottle your beer cold?
As I wrote above, in a scenario where yeast is not readily active I could imagine that encouraging a more rapid O2 pickup via shaking might increase oxidative damage as compared to a scenario where the headspace O2 would diffuse more slowly into the beer.
 

VikeMan

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Can't really explain this experiment then.
I wouldn't even try. Try again with one carefully controlled variable. Then repeat.

(Also keep in mind that any gas laws mentioned apply to oxygenation, not to oxidation, which follows on later.)
 

SwedishBrew

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Like this guy?

They are all identical, besides some difference in headspace then I suppose. ALL of the other 50 bottles tasted good, except these two I shook, which tasted like a different kind of beer. So I can't see any other reason to why just those two I shooked failed.

Taket_al_Tauro, I bottle in room temperature without cold crashing before. And I believe you are right, think introducing O2 faster, via shaking, does more damage. That's the only conclusion I can come up with :)
 
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