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Purging headspace when bottling

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beerhenry

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Am about to bottle a NEIPA for the first time and I understand that a lot of people have issues with oxidation. After some reading I'm convinced that purging the headspace after filling the bottle of O2 is a good way of extending the shelf life. I'll be bottle priming as I don't have any kegging equipment. So to my question...

Is it possible to purge the headspace with the CO2 from the beer? My idea is to fill the bottles and leave the caps on loosely for a period of time (a few hours?) and returning later to cap? The infection risk is obviously present but I think it's small.

Alternately I have CO2 cartridges and a CO2 bike pump at my disposal, though the gas tends to come out very quickly. Maybe filling a balloon with CO2 first?

Any thoughts? If anyone has some any other ideas I'm all ears :)
 

Silver_Is_Money

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LOX-less base malt is a thought. It has no lipoxygenase enzymes from which to become ravaged by oxygen over time.
 

McKnuckle

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To purge one gas with another requires pressure that forces the resident gas out of its occupied space. So I would imagine that since the egress of residual CO2 from the beer would not occur with any significant pressure, O2 from the atmosphere would also freely enter the space, mixing with the CO2.

At some point I assume the space would be occupied 50/50 or at least close to that, maybe leaning towards a little more CO2. Maybe it's better than nothing, but not as effective as a forceful blast of CO2. Also, you'd want to compensate for the loss of absorbed CO2 in terms of priming; the calculators all make an assumption about how much is already in the beer based on temperature.
 

Vale71

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Is it possible to purge the headspace with the CO2 from the beer?
No. As CO2 is leaving the bottle air is entering it at a much faster rate and creating a mixed atmosphere of mostly air. All you'll accomplish is to lose some carbonation (probably not much) and oxidising your beer (probably quite a lot).
 

Vale71

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At some point I assume the space would be occupied 50/50 or at least close to that...
That's really far from reality. Since CO2 has to leave the beer first its release rate will be determined by the diffusion rate of CO2 in water whereas the mix of gases that make up the atmosphere will be entering the bottle at a rate set by the diffusion rate of gases which is about 2 orders of magnitude faster. 99% air and 1% CO2 is probably a much more accurate estimate of the temporary equilibrium that will be reached. In other words this will offer no protection at all.
 

Miraculix

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The first and most effective thing to do is to minimise the headspace. From my experience, 3mm is enough. You need a little bit for liquids to expand, otherwise you risk bottle bombs, but you really want to keep it as small as possible.
 

BrewnWKopperKat

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After some reading I'm convinced that purging the headspace after filling the bottle of O2 is a good way of extending the shelf life.
If you came here looking for consensus on an approach, you probably won't find it. :)

Maybe in a year or two, we'll know which of the recently proposed techniques for bottling NEIPAs works.

If you can be specific on what you were reading, you may get some feedback on those articles - and that may be useful.

Otherwise, move forward with your plan and see what happens.
 
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Here's what I would do. Get a small tank(like paintball gun tank), with a length of hose, a simple regulator and a nozzle to fit into the neck of a bottle. Staying sanitary, fill the bottle up with CO2 to purge the air from it like you would to fill a keg and then fill your bottle with the normal headspace and cap. That should minimize oxidation.
 

Miraculix

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Here's what I would do. Get a small tank(like paintball gun tank), with a length of hose, a simple regulator and a nozzle to fit into the neck of a bottle. Staying sanitary, fill the bottle up with CO2 to purge the air from it like you would to fill a keg and then fill your bottle with the normal headspace and cap. That should minimize oxidation.
This way, you would still just replace a part of the air with co2, leaving a significant amount of O2 in the bottle.

Better way would be to use your system, full the bottle with beer, insert the co2hose into the beer, create bubbles and then cap directly on the co2 foam that you created. This way, you make sure that there is almost only co2 in the headspace!

Keeping the headspace as small as possible also helps here.

Which parts would one need to create this co2 tool you are taking about?
 

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Beermeister32

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After filling bottles, you can leave the caps on loose. Take a picnic tap and hook it up to your CO2 regulator with a couple feet of hose. Set your regulator low for a few lbs of pressure. Then you can pick up a cap and give the headspace a little blast of CO2 before capping. Not "perfect" but will clear a good portion of the O2 prior to capping.
 
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pc_trott

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Forgive me for being a newb, but I thought the O2 in the headspace was necessary to activate the yeast so that they carbonate the beer.
 

balrog

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There's likely plenty of o2 dissolved in the beer for the yeast, which likely don't need the phase of replication as they are pretty numerous already in the just-fermented beer.
 
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Forgive me for being a newb, but I thought the O2 in the headspace was necessary to activate the yeast so that they carbonate the beer.
No, the only time you want oxygen to come in contact with your beer is when it is cooled wort and you are aerating/oxygenating it for the yeast to ferment it out. After it is fermented out, beer and oxygen are no longer friends. When it comes time for packaging, limiting oxygen is important, definitely so with highly hopped beers where it will ruin the color and flavor. The priming sugar is what reinvigorates the yeast to referment the fresh sugar to carbonate the beer. Hope this helps.
 

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There's likely plenty of o2 dissolved in the beer for the yeast, which likely don't need the phase of replication as they are pretty numerous already in the just-fermented beer.
For what I know, oxygen is fast displaced from beer (from wort) in the first days of fermentation, partially because it has this habit of flying away, and partially because the CO2 which is produced by fermentation displaces it.

That said, what I learned so far is that oxygen in the bottle is necessary if you prime in the bottle, but bottling introduces much more oxygen than you would ideally have in your beer. That will ultimately put your shelf-life at risk. This should not be a problem if you tend to scavenge your beer stock within a few weeks from maturation, but it can be a problem if you deal with high OG beers which benefit from a long maturation in the bottle. You risk them ending up with a perceivable oxydization. That's the reason behind those caps which have an oxygen-absorbing sponge on the inner side. Then again, I have no idea how this kind of "smart" caps are effective. Any review is welcome.

I happen to have bought just today my first CO2 cylinder with regulator. My idea was to simply blow the CO2 after having filled the bottle. My idea so far is to not "purge" the bottle from air before filling it. A little oxygen will mix with the beer during the filling operation, and a little oxygen will remain in the bottle due to the imperfect expulsion of air from the bottle before capping. Maybe it's that little which is necessary.

Yet, reading this thread I am considering using my 0,5 microns aerating SS "stone", when and if I will receive it from China, with CO2 and put that inside each bottle for a few seconds. That could purge almost entirely the oxygen. I will certainly experiment with that when (and if) I receive the aerating stone and see what happens with a bottling targeting zero CO2.

As a side note regarding long-time maturation (more than 1 year) for what I have read it is good practice to "wax" your bottles, because ordinary crown caps don't close the bottles perfectly.
 

McKnuckle

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That said, what I learned so far is that oxygen in the bottle is necessary if you prime in the bottle, but bottling introduces much more oxygen than you would ideally have in your beer.
Oxygen is needed so that yeast can replicate and increase their population once being pitched into wort. You do not need to add oxygen to beer for it to carbonate, or to worry about that at all.

I have purged O2 from many a serving keg using CO2 from the fermenter, and carbonated naturally in it with priming sugar. In some cases I have put the priming sugar in the keg before purging, so it is full of CO2 and literally not opened until the beer has been consumed.

These kegs are more free of oxygen than any bottle could hope to be, and yet they carbonate just fine. They take the same 10-14 day period to carbonate as bottles.
 

Birrofilo

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Oxygen is needed so that yeast can replicate and increase their population once being pitched into wort. You do not need to add oxygen to beer for it to carbonate, or to worry about that at all.

I have purged O2 from many a serving keg using CO2 from the fermenter, and carbonated naturally in it with priming sugar. In some cases I have put the priming sugar in the keg before purging, so it is full of CO2 and literally not opened until the beer has been consumed.

These kegs are more free of oxygen than any bottle could hope to be, and yet they carbonate just fine. They take the same 10-14 day period to carbonate as bottles.
I have always given for granted that the tiny amount of yeast which residuates from the bottling process (considering that we bottle "clear" beer) needed to reproduce somehow for the carbonation of the beer to be successful.

What you tell me is very interesting as it suggests to me that using an aeration stone connected to a CO2 would be a safe way to proceed. The aeration stone should make it easy to cap "on the foam" and there is no risk of failed carbonation.
 

Beermeister32

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No O2 at bottling, you would oxidize your beer. Some commercial bottling machines which process carbonated beer do a slight agitation or bump to foam up the beer with CO2 foam and drive off Oxygen prior to automatic capping.

For home bottling:

"What is the difference between aerobic and anaerobic respiration in yeast? The yeast simply switches from aerobic respiration (requiring oxygen) to anaerobic respiration (not requiring oxygen) and converts its food without oxygen in a process known as fermentation."

So minimize the Oxygen at this stage, the yeast will do fine without you adding a bunch of flavor degrading Oxygen.
 

Miraculix

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No O2 at bottling, you would oxidize your beer. Some commercial bottling machines which process carbonated beer do a slight agitation or bump to foam up the beer with CO2 foam and drive off Oxygen prior to automatic capping.

For home bottling:

"What is the difference between aerobic and anaerobic respiration in yeast? The yeast simply switches from aerobic respiration (requiring oxygen) to anaerobic respiration (not requiring oxygen) and converts its food without oxygen in a process known as fermentation."

So minimize the Oxygen at this stage, the yeast will do fine without you adding a bunch of flavor degrading Oxygen.
He was was talking about using an aeration stone to bring co2 into the beer and create co2 foam!

To me it sounds legit.
 

Beermeister32

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I think the amount of beer displaced by pushing an aeration stone into the bottle would increase the headspace when the stone was removed. So you would end up with a much larger headspace than you planned.
 

bu_gee

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Let me make it complicated with my overactive and, let me just get it out, excessively cheap imagination:

First, CO2 is about 25% heavier than air so you can actually pour it through the air and displace air in a vessel if you wanted to. Check out YouTube for all of the videos of people putting out candles using CO2 produced from baking soda and vinegar. So, that is technically an option.

So my thinking is to go buy some giant balloons and collect your offgassing during fermentation. As my electronics professor used to say about triple integrals in polar coordinates: This is a trivial task which I'm sure you won't have any problems with.

During bottling use a straw or hose to fill every bottle with CO2 from the bottom immediately before filling with beer, cap and enjoy that all that extra work was way more environmentally friendly than a CO2 bottling setup.

Seriously though, don't do this. It is way more work for what is likely to be, at best, a marginally better result.

I have to agree that a loose cap is unlikely to achieve the result you're looking for. Even in the unlikely case the purge was orderly, you're likely to disturb it while sealing the bottle and your carbonation level will be a crap shoot to boot.

My LHBS sells caps that allegedly absorb O2 from the head space. I've never used them. I doubt it is a con, but I also can't speak to how much of a difference they make.

Ultimately, though, if you've reached the point in your brewing that O2 in the headspace has become a leading problem, it is probably time to upgrade your equipment with kegging and forced bottling setup.
 

Vale71

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First, CO2 is about 25% heavier than air so you can actually pour it through the air and displace air in a vessel if you wanted to. Check out YouTube for all of the videos of people putting out candles using CO2 produced from baking soda and vinegar. So, that is technically an option.
For the umptieth time, gases don't displace each other. They mix freely and readily and their being heavier or lighter is immaterial. This is actually what sets them apart from liquids and solids. A gas will always, invariably expand until limited by a solid or liquid barrier. The fact that there may be other gases in the way is immaterial.

The reason the candle in your example is put out is because you create a CO2/air mix by causing a violent and sudden release of CO2 (gases don't diffuse at the speed of light so there is a time delay involved) in a partially enclosed space which lowers the concentration of O2 to below the minimum oxygen concentration required to sustain the flame. Depending on the type of material being burnt this limit might be as high as 17% oxygen which is not much below the standard atmospheric concentration of 21% and certainly more than enough to cause your beer to become oxidized. Don't be fooled into thinking that because the flame is put out that there must be no oxygen at all present.

The only way to succesfully displace most of the air is through foaming, as foam is filled with 100% CO2 coming from the beer itself and that CO2 is (at least temporarily) contained in the bubble's shell so that it cannot freely mix with surrounding air.
 
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bu_gee

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For the umptieth time, gases don't displace each other. They mix freely and readily and their being heavier or lighter is immaterial. This is actually what sets them apart from liquids and solids. A gas will always, invariably expand until limited by a solid or liquid barrier. The fact that there may be other gases in the way is immaterial.

The reason the candle in your example is put out is because you create a CO2/air mix by causing a violent and sudden release of CO2 (gases don't diffuse at the speed of light so there is a time delay involved) in a partially enclosed space which lowers the concentration of O2 to below the minimum oxygen concentration required to sustain the flame. Depending on the type of material being burnt this limit might be as high as 17% oxygen which is not much below the standard atmospheric concentration of 21% and certainly more than enough to cause your beer to become oxidized. Don't be fooled into thinking that because the flame is put out that there must be no oxygen at all present.

The only way to succesfully displace most of the air is through foaming, as foam is filled with 100% CO2 coming from the beer itself and that CO2 is (at least temporarily) contained in the bubble's shell so that it cannot freely mix with surrounding air.
What part of "don't do this" wasn't clear? This was a mostly tounge-in-cheek post. Please read my entire post before ripping me a new one.

There is also no 100% ever, so let's just dispense of that altogether and agree that we're all just working with different quality crap. Just like everything else we do at home scale, it is mitigation and not a well controlled industrial technique.
 
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bu_gee

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For the umptieth time, gases don't displace each other. They mix freely and readily and their being heavier or lighter is immaterial. This is actually what sets them apart from liquids and solids. A gas will always, invariably expand until limited by a solid or liquid barrier. The fact that there may be other gases in the way is immaterial.

The reason the candle in your example is put out is because you create a CO2/air mix by causing a violent and sudden release of CO2 (gases don't diffuse at the speed of light so there is a time delay involved) in a partially enclosed space which lowers the concentration of O2 to below the minimum oxygen concentration required to sustain the flame. Depending on the type of material being burnt this limit might be as high as 17% oxygen which is not much below the standard atmospheric concentration of 21% and certainly more than enough to cause your beer to become oxidized. Don't be fooled into thinking that because the flame is put out that there must be no oxygen at all present.
Also, this video shows an experiment, which I have personally done with my kids, that clearly demonstrates that the density of the gas matters and they do displace each-other, at least temporarily. The candles are not in an enclosed space, unless you're claiming that the entire room is the size you're talking about, which would be a dangerous amount of CO2 for humans to be around.


While, you are correct that about 18% oxygen is enough to put out a candle, you can't make the case that the amount of CO2 generated by that amount of bicarb could drop the concentration in the whole room to that level.
 

Vale71

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The CO2 expands in all directions, including downwards. Plus in this video you can clearly see a downdraft as the flame is extinguished (the smoke spreads out downwards instead of going up) and that's because the CO2 being generated is colder than the surrounding air. This is due to the fact that the reaction that just occured in the pitcher is endothermic.
 

bu_gee

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The CO2 expands in all directions, including downwards. Plus in this video you can clearly see a downdraft as the flame is extinguished (the smoke spreads out downwards instead of going up) and that's because the CO2 being generated is colder than the surrounding air. This is due to the fact that the reaction that just occured in the pitcher is endothermic.
So, colder, therefore more dense than the usual 25% by the molecular mass alone.
 

Vale71

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Don't let this parlor trick fool you. What the guy is doing is creating a downdraft of colder air that's carrying the CO2 downwards (while at the same time creating an oxygen-impoverished mixture) and aiming it at the candle. From the looks of it the flame gets extinguished more through the action of the downdraft itself than from actual oxygen starvation.

You could try the same experiment with CO2 from a cylinder that's at the same temperature as the surrounding air and see if you get the same effect.
 

bu_gee

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You could try the same experiment with CO2 from a cylinder that's at the same temperature as the surrounding air and see if you get the same effect.
Why does cold air sink? Because it is more dense. Why does CO2 sink? Because it is more dense.
 
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Vale71

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Why does cold air sink? Because it is more dense. Why does CO2 sink? Because it is more dense.
Okay. So you're saying we're all dead because we're swimming in a layer of pure CO2. Reality begs to differ.
 

McKnuckle

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Linked below is a pretty revealing scientific article which discusses the erroneous perception that CO2 sinks. Worth at least a partial read for those so inclined. Bottom line is that CO2 does not sink, but the variables related to gas mixing and stratification are complex - moreso than anyone typically addresses here on the forum. Very interesting.

THE LEGEND OF CARBON DIOXIDE HEAVINESS
https://caves.org/pub/journal/PDF/v71/cave-71-01-100.pdf
 

Vale71

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It is basic buoyancy and denser items, fluids or solids, sink in comparatively less dense fluids, and, yes, if they're fluid they'll likely, with few exceptions, eventually mix, which is something I've been saying all along, but TEMPORARILY they don't and if you don't WANT to understand, that only affects you, not reality.
Okay, I'll bite. You say they TEMPORARILY don't mix. For how long? What is the event or condition that makes them suddenly start mixing? Is it a fixed amount of time? Can you control that behaviour at all?
 

bu_gee

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Okay, I'll bite. You say they TEMPORARILY don't mix. For how long? What is the event or condition that makes them suddenly start mixing? Is it a fixed amount of time? Can you control that behaviour at all?
Now that is a complicated subject. Diffusion rates are dependent on a number of factors including density, kinetic energy, molecular "compatibility" (analog to oil and water), etc.

Look, the CO2 once poured from that guy's bottle is probably too diffuse to do what it did to the candle in just a few seconds or another 4 inches and probably undetectably diffused into the room within a minute. This I just a sense of how I've seen it behave, not actual math, well, because I don't hate myself that much. 😁
 

Taket_al_Tauro

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I'm unsure how reputable a source Wikipedia is, but how would one explain the Lake Nyos dysaster?

If it is false that CO2 at least TEMPORARILY sinks because it is heavier, then did this happen just because of the sheer amount of CO2 released all of a sudden by the eruption?
So in this case, the CO2 diffused rather than sinked onto nearby villages and its concentration increased to a level high enough to kill that many people and animals?

From Wikipedia:
"

On 21 August 1986, a limnic eruption at Lake Nyos in northwestern Cameroon killed 1,746 people and 3,500 livestock.

The eruption triggered the sudden release of about 100,000–300,000 tons (1.6 million tons, according to some sources) of carbon dioxide (CO
2).[1][2] The gas cloud initially rose at nearly 100 kilometres per hour (62 mph) and then, being heavier than air, descended onto nearby villages, displacing all the air and suffocating people and livestock within 25 kilometres (16 mi) of the lake.[3][4]

"
 

Beermeister32

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I believe natural gas also exhibits the same behavior. When a stove is valve is left on there is a temporary stratification of the air favoring the natural gas more towards the floor. Temporarily of course!
 

Vale71

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I'm unsure how reputable a source Wikipedia is, but how would one explain the Lake Nyos dysaster?

If it is false that CO2 at least TEMPORARILY sinks because it is heavier, then did this happen just because of the sheer amount of CO2 released all of a sudden by the eruption?
So in this case, the CO2 diffused rather than sinked onto nearby villages and its concentration increased to a level high enough to kill that many people and animals?

From Wikipedia:
"

On 21 August 1986, a limnic eruption at Lake Nyos in northwestern Cameroon killed 1,746 people and 3,500 livestock.

The eruption triggered the sudden release of about 100,000–300,000 tons (1.6 million tons, according to some sources) of carbon dioxide (CO
2).[1][2] The gas cloud initially rose at nearly 100 kilometres per hour (62 mph) and then, being heavier than air, descended onto nearby villages, displacing all the air and suffocating people and livestock within 25 kilometres (16 mi) of the lake.[3][4]

"
That description of the phenomenon is rife with inaccuracies. Yes, if a huge amount of CO2 is released it will diffuse in all directions, including into the valleys. There it will not displace "all the air" neither does it need to do so as CO2 concentrations as low as 10% can already be deadly due to CO2's inherent toxicity. Valleys are usually hit the heaviest because they are more protected from air currents than an open plain, so it can take quite a long time for CO2 to dissipate mostly through gas diffusion. Since CO2's toxicity is the combined effect of exposure level and exposure duration valleys unfortunately are were you'll find most of the fatalities. There is no need to postulate the existence of "CO2 rivers" to explain this tragic phenomenon.
 
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bu_gee

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I'm unsure how reputable a source Wikipedia is, but how would one explain the Lake Nyos dysaster?

If it is false that CO2 at least TEMPORARILY sinks because it is heavier, then did this happen just because of the sheer amount of CO2 released all of a sudden by the eruption?
So in this case, the CO2 diffused rather than sinked onto nearby villages and its concentration increased to a level high enough to kill that many people and animals?

From Wikipedia:
"

On 21 August 1986, a limnic eruption at Lake Nyos in northwestern Cameroon killed 1,746 people and 3,500 livestock.

The eruption triggered the sudden release of about 100,000–300,000 tons (1.6 million tons, according to some sources) of carbon dioxide (CO
2).[1][2] The gas cloud initially rose at nearly 100 kilometres per hour (62 mph) and then, being heavier than air, descended onto nearby villages, displacing all the air and suffocating people and livestock within 25 kilometres (16 mi) of the lake.[3][4]

"
This goes back to it being a very complicated intersection of fluid dynamics and biology, which is pretty much what this entire thread is.

Volcanic eruptions also add into the mix particles which drag gases down along with them. If we can't control a small amount of CO2 in a bottle, I think a volcano is going to be well out of our grasp. :p

Edit: I should have said "describe" instead of "control."
 
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bu_gee

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Okay, I'll bite. You say they TEMPORARILY don't mix. For how long? What is the event or condition that makes them suddenly start mixing? Is it a fixed amount of time? Can you control that behaviour at all?
Now I see the problem, you think by "temporary" I meant that it doesn't mix for a while and then suddenly it all mixes. That is not what I intended to imply and I apologize for my poor choice of words which I will admit were imprecise due to convenience.

What I meant by this is that the diffusion rates are slow enough that localized pockets of gases can have effects that approximate gases not being mixed for a short duration of time while the diffusion processes do their work.

Now, with that being said, what are the most precise 1-3 words to describe this?
 

Vale71

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Now I see the problem, you think I meant that it doesn't mix for a while and then suddenly it all mixes. That is not what I intended to imply and I apologize for my poor choice of words which I will admit were imprecise due to convenience.

What I meant by this is that the diffusion rates are slow enough that localized pockets of gases can have effects that approximate gases not being mixed for a short duration of time while the diffusion processes do their work.

Now, with that being said, what are the most precise 1-3 words to describe this?
The whole point of the discussion is that you cannot really displace air through CO2 unless it's a closed container and you perform a complicated series of evacuation cycles. CO2 released in an open container, be it released by the beer itself through outgassing or via a short burst from a gas cylinder will immediately start mixing with the extant atmosphere. No actual displacement takes place, there will just be a continuous gradient in the composition of the gas mix. What this means in the specific case at hand (bottling beer with as little O2 as possible) is that all you will achieve is a (possibly significant) reduction of the amount of O2 but any belief that CO2 will completely replace the air in the headspace is unfounded.
 
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