Purging headspace when bottling

[InspectorJon]

I'm kind of afraid to ask this question as it may start a whole new round of...discussion. Does the rate of dilution/mixing with the air in the room have any relationship to the size of the opening at the top of the container? If I quickly open my fermentor with a small opening in the top to drop in some hops and seal it back up how much air is going to mix with the Co2 in the container?

 

[Beermeister32]

Another interesting experiment you can do which visually shows this is throwing a chunk of dry ice into a 5 gallon bucket with some warm water inside, and set it on the floor. The gas visually pours out the top of the bucket and down the sides and settles to the floor below. Then it would diffuse into the room air.

Which might suggest temporary gas "clouding" would be beneficial to some operations, acknowledging it is temporary until it blends with the surrounding air.

 

[bu_gee]

Another interesting experiment you can do which visually shows this is throwing a chunk of dry ice into a 5 gallon bucket with some warm water inside, and set it on the floor. The gas visually pours out the top of the bucket and down the sides and settles to the floor below. Then it would diffuse into the room air.

Which might suggest temporary gas "clouding" would be beneficial to some operations, acknowledging it is temporary until it blends with the surrounding air.

If I'm not mistaken, in that experiment the clouds are actually water vapor clouds, just like in the sky. While vapor is technically not a gas, in this case the droplets are so small that they effectively behave like heavy gas "particles.". There is probably a better word for that, but I can't come up with it at the moment.

Eventually the droplets will get bigger and settle or evaporate into the air.

 

[Taket_al_Tauro]

If I quickly open my fermentor with a small opening in the top to drop in some hops and seal it back up how much air is going to mix with the Co2 in the container?

The opening, yes the opening! It is our last resort when all blankets fail. Glad I changed from buckets to Speidels some time ago. But I'm not ready to go the "stainless + crazy O2 free dry hopping contraption " route yet.

 

[bu_gee]

I'm kind of afraid to ask this question as it may start a whole new round of...discussion. Does the rate of dilution/mixing with the air in the room have any relationship to the size of the opening at the top of the container? If I quickly open my fermentor with a small opening in the top to drop in some hops and seal it back up how much air is going to mix with the Co2 in the container?

A lot, but natural diffusion wouldn't be your biggest problem here. Falling objects can drag a significant amount of air along with them. But that also depends on your definition of significant. For most brewing purposes and for most people, I would venture that this is an acceptable amount of O2.

Edit: NATURAL diffusion.

 

[InspectorJon]

A lot.

Darn, I wish he had said "a little". These words are so imprecise. So how much is "a lot" and how do we decide when "a lot" is "too much"? Will putting "some" co2 into the beer below the head space of a bottle and creating co2 bubbles we cap on top of help a little or a lot?

 

[Vale71]

If I'm not mistaken, in that experiment the clouds are actually water vapor clouds, just like in the sky. While vapor is technically not a gas, in this case the droplets are so small that they effectively behave like heavy gas "particles.". There is probably a better word for that, but I can't come up with it at the moment.

Eventually the droplets will get bigger and settle or evaporate into the air.

Vapor technically is a gas (it's the gas phase of H2O) and it's invisible. It's a good thing because it's all around us mixed into the atmosphere.

What you see coming out of this type of fog machine is condensed vapor which is nothing but plain old water. Being a liquid the droplets will drop (nomen omen) to the floor, albeit very slowly because of aerodinamic drag and possibly partly evaporating again on the way down. Convection is also involved as dry ice will create a convective cell due do it constantly absorbing heat from the atmosphere in order to sublimate to CO2 gas. The droplets evaporating also will power the convective cell as they too need heat to become vapor again and this will keep cooling the air further.

 

[Cloud Surfer]

I pressure transfer out of my stainless conical fermenter into a keg that’s been CO2 purged and pre-filled with the priming sugar.

I then use a bottling gun. The gun has a liquid line and a CO2 line. I put the gun in the bottle and pull the CO2 trigger to fill the bottle with CO2 then pull the liquid trigger and fill the bottle to overflowing. I cap immediately. This is about as oxygen free as I can get it on a home brew scale.

When I used to use the bottling bucket I was always worried about oxidation and infection in an open system, and felt like I had to work as fast as I could to get beer into bottle. The whole bottling process is so calm now.

 

[day_trippr]

fwiw, molecular motion alone diffuses gases...

 

[Vale71]

I pressure transfer out of my stainless conical fermenter into a keg that’s been CO2 purged and pre-filled with the priming sugar.

I then use a bottling gun. The gun has a liquid line and a CO2 line. I put the gun in the bottle and pull the CO2 trigger to fill the bottle with CO2 then pull the liquid trigger and fill the bottle to overflowing. I cap immediately. This is about as oxygen free as I can get it on a home brew scale.

When I used to use the bottling bucket I was always worried about oxidation and infection in an open system, and felt like I had to work as fast as I could to get beer into bottle. The whole bottling process is so calm now.

Counterpressure filling with actual evacuation and purging is possible at the homebrew level too, so what you're doing is only the next best thing. Your belief that you're actually filling the bottle with CO2 is incorrect which is the whole point of the lengthy discussion we've been having. Not only is the CO2 mixing with air, but as you calmly fill your bottles atmospheric oxygen is also calmly diffusing back into the bottle (which is still a completely open system) and into the beer.

 

[Vale71]

fwiw, molecular motion alone diffuses gases...

Damn you, emergent behaviour!!

 

[connell89]

You are all hurting my head and making homebrewing why to complicated. Purge the bottles with CO2, fill with beer and cap. Drink before oxidation sets in. But I think somewhere in the first 10 posts, your question was answered. No, don't leave the caps on loose or try it and see what happens.

 

[doug293cz]

Thread locked for cooling down period, and clean up.

doug293cz
HBT Moderator

 

[doug293cz]

Thread is reopened. Stay on topic, and don't get personal.

doug293cz

 

[Snuffy]

The best solution would be to create a sealed environment totally filled with carbon dioxide, enter it via a vacuum portal in an astronaut suit and then bottle away with no worries.

 

[Birrofilo]

The best solution would be to create a sealed environment totally filled with carbon dioxide, enter it via a vacuum portal in an astronaut suit and then bottle away with no worries.

In hospitals they have oxygen tents. A CO2 tent could be devised.
Instead of an astronaut suit, a diver setup could be used. You need no wetsuit and fins, only the respirator.
The thing is more feasible than at first thought.
Actually I wouldn't be surprised if anybody did anything like that
Problem I see is the cost of the CO2.

 

[Miraculix]

I pressure transfer out of my stainless conical fermenter into a keg that’s been CO2 purged and pre-filled with the priming sugar.

I then use a bottling gun. The gun has a liquid line and a CO2 line. I put the gun in the bottle and pull the CO2 trigger to fill the bottle with CO2 then pull the liquid trigger and fill the bottle to overflowing. I cap immediately. This is about as oxygen free as I can get it on a home brew scale.

When I used to use the bottling bucket I was always worried about oxidation and infection in an open system, and felt like I had to work as fast as I could to get beer into bottle. The whole bottling process is so calm now.

If you can, don't purge the bottles, but create foam with your co2 once the bottles are filled and immediately cap directly on the co2 foam. This is the only way how you get almost no O2 trapped in the bottle. Vale71 already explained why purging does not work, capping on co2 foam ensures minimum oxygen in the bottle.

 

[Birrofilo]

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.

Purging is certainly possible as you will see in the thread and pictures in the threads which was quoted in text #11 of this thread, which I consider a very interesting reading for all brewers.

Regarding going away for a few hours, I don't think it would work because the bottle is opened and the diffusion will prevail. Just purge the neck of the bottle and cap immediately.

This text, from the blog of Columbia University, explains how in a confined environment the CO2 gas molecules tend to stratify over the wine, while in an open bottle diffusion will make your gases escape outside of the bottle neck

https://blogs.ei.columbia.edu/2020/09/23/carbon-dioxide-distribution-atmosphere/
Stratification of heavy gases (gases with a high molecular weights) is a well-known concept and is the object of regulation on labour safety and other safety compulsory measures, regarding CO2, propane, butane and other heavy gases. People die because of stratification of gases!

Those who want more information can search for norms and guidelines about work into silos for grain stockage, or norms about underground parking places and LPG vehicles.

 

[BrewnWKopperKat]

back to the original question.

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

FWIW, these two topics offer approaches that result in bottles that are good for 40+ days.

https://www.homebrewtalk.com/thread...le-conditioned-ipa.653784/page-6#post-8877059

https://www.homebrewtalk.com/thread...n-and-alternatives.686774/page-2#post-9054118

eta: I will not be suprised to see "rebuttal" posts (with regard to the processes in those topcis) in 45 to 90 days. Better beer can be made when processes are "put to the test".

 

[Snuffy]

In hospitals they have oxygen tents. A CO2 tent could be devised.
Instead of an astronaut suit, a diver setup could be used. You need no wetsuit and fins, only the respirator.
The thing is more feasible than at first thought.
Actually I wouldn't be surprised if anybody did anything like that
Problem I see is the cost of the CO2.

Or one of those hazardous materials rigs with the plastic arm gloves. That would minimize the volume and require less CO2 and no breathing apparatus.https://i.pinimg.com/originals/82/ba/60/82ba606cc57683cad31c8e72cfaca929.jpg

 

[doug293cz]

Purging is certainly possible as you will see in the thread and pictures in the threads which was quoted in text #11 of this thread, which I consider a very interesting reading for all brewers.

Regarding going away for a few hours, I don't think it would work because the bottle is opened and the diffusion will prevail. Just purge the neck of the bottle and cap immediately.

This text, from the blog of Columbia University, explains how in a confined environment the CO2 gas molecules tend to stratify over the wine, while in an open bottle diffusion will make your gases escape outside of the bottle neck

https://blogs.ei.columbia.edu/2020/09/23/carbon-dioxide-distribution-atmosphere/
Stratification of heavy gases (gases with a high molecular weights) is a well-known concept and is the object of regulation on labour safety and other safety compulsory measures, regarding CO2, propane, butane and other heavy gases. People die because of stratification of gases!

Those who want more information can search for norms and guidelines about work into silos for grain stockage, or norms about underground parking places and LPG vehicles.

That article is full of misinformation. Gases get less dense as you go higher in the atmosphere*, contrary to what that article says. And headspace gases do not stratify in an enclosed space, just like they don't stratify in an open space (see the videos posted earlier in this thread.)

The heavy gas stratification you mention is a transient effect that occurs when the source is supplying heavy gas faster than diffusion (or convection/advection) can cause it to mix with the ambient atmosphere. Once the source is shut off, the heavy gas will dissipate into the atmosphere. You are correct that safety hazards abound until the excess concentration of gas dissipates.

* "the table interpolates to the standard mean sea level values of 15 °C (59 °F) temperature, 101,325 pascals (14.6959 psi) (1 atm) pressure, and a density of 1.2250 kilograms per cubic meter (0.07647 lb/cu ft). The tropospheric tabulation continues to 11,000 meters (36,089 ft), where the temperature has fallen to −56.5 °C (−69.7 °F), the pressure to 22,632 pascals (3.2825 psi), and the density to 0.3639 kilograms per cubic meter (0.02272 lb/cu ft)".


Brew on

 

[Birrofilo]

You are correct that safety hazards abound until the excess concentration of gas dissipates.

Letting "long-term" gas mixing apart for the moment [I am not convinced, but it is not relevant for the homebrewer purging the headspace], if in the short term the heavier gases tend to stratify, while the CO2 cylinder supplys excess concentration of the gas, then injecting CO2 into the neck of the bottle, and capping without delay, should be a valid way to reduce oxigenation of the beer, as empirically confirmed in another thread which was begun by @Tacket_al_Tauro.

If time is needed for the gases to mix, then purging the headspace and capping makes sense because the gas which is trapped inside the neck of the bottle will be most CO2 with some quantity or ambient air. Oxygen will not be entirely eliminated but certainly reduced, which explains the empirical evidence.

 

[Taket_al_Tauro]

Letting "long-term" gas mixing apart for the moment [I am not convinced, but it is not relevant for the homebrewer purging the headspace], if in the short term the heavier gases tend to stratify, while the CO2 cylinder supplys excess concentration of the gas, then injecting CO2 into the neck of the bottle, and capping without delay, should be a valid way to reduce oxigenation of the beer, as empirically confirmed in another thread which was begun by @Tacket_al_Tauro.

I think in the specific case of purging headspaces, the way it works has more to do with displacement of air by the flow of CO2 rather than stratification.
You give a burst of CO2 into the neck of the bottle and that forces most of the air out. I also believe you should cap immediately, or at least as quickly as possible, for this method to work best.

You are right that this won't remove all O2 from the headspace, but at the very least it should decrease its concentration significantly.

 

[Birrofilo]

I think in the specific case of purging headspaces, the way it works has more to do with displacement of air by the flow of CO2 rather than stratification.
You give a burst of CO2 into the neck of the bottle and that forces most of the air out.

The doubt arises whether one would manage to displace the air in the bottleneck, even for 10 seconds, if the gas used was helium or hydrogen. I suspect they would immediately mix with ambient air and by the time you close the cylinder tap, put down the hose, put the cap on the bottle, and seal the bottle, ambient air would re-enter the bottle faster than if the injected gas is CO2.

What I think it is clear is that in any case purging with CO2 is certainly possible.

 

[Miraculix]

That is why creating foam with the co2, instead of purging, is more effective.

 

[Taket_al_Tauro]

The doubt arises whether one would manage to displace the air in the bottleneck, even for 10 seconds, if the gas used was helium or hydrogen. I suspect they would immediately mix with ambient air and by the time you close the cylinder tap, put down the hose, put the cap on the bottle, and seal the bottle, ambient air would re-enter the bottle faster than if the injected gas is CO2.

What I think it is clear is that in any case purging with CO2 is certainly possible.

Thing is, in my case I do not have to wait even 10 seconds to seal the bottle. I can seal it literally immediately after the purging burst, because I use swing tops.
However, also folks using crown caps seem to report success using this method, so I guess it works also if you delay the sealing a bit. But in this case I think it is very important to put at least the crown cap immediately on the bottle after the purge.

That is why creating foam with the co2, instead of purging, is more effective.

Do you have any evidence or direct experience to support that?
It sure makes sense but the only time I was able to test that, I did not see a difference. But of course it was just one data point...

 

[Birrofilo]

Do you have any evidence or direct experience to support that?
It sure makes sense but the only time I was able to test that, I did not see a difference. But of course it was just one data point...

If memory serves, you actually were able to test that.
In the other thread, you report how you made an attempt at bottling with the "splashing" tecnique, letting the beer foam while the bottle is filled, and for what I remember you find that the beer was actually not perceivably different than the others which underwent the CO2 purge. Yet, you stated that you will go on with the purging tecninque (and so will I. Splashing is creepy )

The logic behind the splashing technique is that the beer will release CO2 instead of incorporate O2. I would expect both things to happen (beer releases CO2 but also incorporates O2 in the process) but we have some empirical evidence that splashing might actually reduce beer oxidation...

I will certainly make some experiments with the splashing technique myself.

I tried to make some foam with a Chinese ultrasound base but my ale, at the moment of bottling, doesn't have enough dissolved CO2 for this contraption to work. Or maybe my contramption is defective.

https://www.amazon.it/gp/product/B07YDKV37N/ref=ppx_yo_dt_b_asin_title_o00_s00

 

[Miraculix]

Thing is, in my case I do not have to wait even 10 seconds to seal the bottle. I can seal it literally immediately after the purging burst, because I use swing tops.
However, also folks using crown caps seem to report success using this method, so I guess it works also if you delay the sealing a bit. But in this case I think it is very important to put at least the crown cap immediately on the bottle after the purge.



Do you have any evidence or direct experience to support that?
It sure makes sense but the only time I was able to test that, I did not see a difference. But of course it was just one data point...

Yes, logic.

Also, somebody here in the forum did some side by side comparisons, capping directly on foam was superior to all the other things he tried.. pruging, leaving it as it is, minimising headspace in general.... it was pretty obvious, the colour changed on all the other ones. Not the same amount, but the change with capping on the foam was the smallest.

 

[Miraculix]

If memory serves, you actually were able to test that.
In the other thread, you report how you made an attempt at bottling with the "splashing" tecnique, letting the beer foam while the bottle is filled, and for what I remember you find that the beer was actually not perceivably different than the others which underwent the CO2 purge. Yet, you stated that you will go on with the purging tecninque (and so will I. Splashing is creepy )

The logic behind the splashing technique is that the beer will release CO2 instead of incorporate O2. I would expect both things to happen (beer releases CO2 but also incorporates O2 in the process) but we have some empirical evidence that splashing might actually reduce beer oxidation...

I will certainly make some experiments with the splashing technique myself.

I tried to make some foam with a Chinese ultrasound base but my ale, at the moment of bottling, doesn't have enough dissolved CO2 for this contraption to work. Or maybe my contramption is defective.

https://www.amazon.it/gp/product/B07YDKV37N/ref=ppx_yo_dt_b_asin_title_o00_s00

Splashing? No. Injecting CO2 into the surface of the beer, creating foam filled with co2. Splashing is not a good idea.

 

[Taket_al_Tauro]

Yes, logic.

Also, somebody here in the forum did some side by side comparisons, capping directly on foam was superior to all the other things he tried.. pruging, leaving it as it is, minimising headspace in general.... it was pretty obvious, the colour changed on all the other ones. Not the same amount, but the change with capping on the foam was the smallest.

Could you point me to that thread or post you mentioned? I would be very interested to see it.
Not questioning the logic behind it (seems logic to me as well, and also the big guys utilize this trick of making the beer foam up when bottling, so they surely have their good reasons). But I would be interested to see if someone at the homebrew level found indeed a difference vs. the (arguably) simpler purging trick.

 

[Miraculix]

Could you point me to that thread or post you mentioned? I would be very interested to see it.
Not questioning the logic behind it (seems logic to me as well, and also the big guys utilize this trick of making the beer foam up when bottling, so they surely have their good reasons). But I would be interested to see if someone at the homebrew level found indeed a difference vs. the (arguably) simpler purging trick.

I'm not tlaking about making the beer foam, but to inject co2 underneath the surface of the beer and create co2 foam this way! Otherwise, bottle conditioning would't be possible.

The Thread is somewhere in here... I honestly do not remember the title or the author.

 

[Taket_al_Tauro]

If memory serves, you actually were able to test that.
In the other thread, you report how you made an attempt at bottling with the "splashing" tecnique, letting the beer foam while the bottle is filled, and for what I remember you find that the beer was actually not perceivably different than the others which underwent the CO2 purge. Yet, you stated that you will go on with the purging tecninque (and so will I. Splashing is creepy )

The logic behind the splashing technique is that the beer will release CO2 instead of incorporate O2. I would expect both things to happen (beer releases CO2 but also incorporates O2 in the process) but we have some empirical evidence that splashing might actually reduce beer oxidation...

I will certainly make some experiments with the splashing technique myself.

I tried to make some foam with a Chinese ultrasound base but my ale, at the moment of bottling, doesn't have enough dissolved CO2 for this contraption to work. Or maybe my contramption is defective.

https://www.amazon.it/gp/product/B07YDKV37N/ref=ppx_yo_dt_b_asin_title_o00_s00

I wouldn't put much emphasis on the reckless "splashing technique " for the time being...
For one, this would make the "closed transfer to keg" guys totally freak out, and we poor bottlers would definitely lose all credibility (rightly so, probably).

Second, I succeeded at that "technique " only once, on a single bottle of a not-so-much hop forward beer (albeit lightly dry hopped).

Third, it is very difficult to get the foaming right when doing this. Sometimes it foams up too much, and you have trouble finishing filling the bottle. Sometimes it doesn't foam up enough for it to work.
I think it is very difficult to have it work in a practicable way...

Still, I do indeed believe that if you have active yeast helping you, the O2 introduced during transferring and bottling has a less prominent effect compared to the O2 that remains trapped in the headspace.
Otherwise we should have our NEIPAs turn brown every single time...

 

[Taket_al_Tauro]

I'm not tlaking about making the beer foam, but to inject co2 underneath the surface of the beer and create co2 foam this way! Otherwise, bottle conditioning would't be possible.

The Thread is somewhere in here... I honestly do not remember the title or the author.

I understood that.
I was just saying that the big boys do something similar, but on the basis of fully carbed beer. They apparently inject a high pressure, very brief and very thin burst of deox water, which makes the beer foam up. Then they cap on foam.

 

[BrewnWKopperKat]

Also, somebody here in the forum did some side by side comparisons,

These are two of the topics (with direct links to results).

https://www.homebrewtalk.com/thread...le-conditioned-ipa.653784/page-6#post-8877059

https://www.homebrewtalk.com/thread...n-and-alternatives.686774/page-2#post-9054118

 

[BrewnWKopperKat]

The Thread is somewhere in here... I honestly do not remember the title or the author.

Could you point me to that thread or post you mentioned?

@Taket_al_Tauro, I may have additional links in my notes. If I can find them, I'll pass them along.

 

[Birrofilo]

I'm not tlaking about making the beer foam, but to inject co2 underneath the surface of the beer and create co2 foam this way! Otherwise, bottle conditioning would't be possible.

The Thread is somewhere in here... I honestly do not remember the title or the author.

It was myself thinking aloud about using an aeration stone with CO2 in order to have the beer bubble and cap on foam. You made a comment that "it seems legit".

A doubt was raised in that thread, that the volume of the aeration stone, once extracted from the beer, would create an empty space on the bottleneck.

Still I want to make an attempt at it, maybe by immersing in the beer only a part of the aeration stone. I have a hunch that it might work, but cannot say until I try.

I have received my 0,2 micron aeration stone from China only a few days ago and I could only test it to oxygenate a "sugar wash" for distilling purposes. Besides, the test was not very encouraging because the oxygen came immediately on top and bursted, because sugar washes have no proteins to make a foam. Yet, I had the suspect that the stone which was sent to me was not 0,2 micron (used with cylinders) but 5 microns (used with aquarium pumps).

 

[Miraculix]

It was myself thinking aloud about using an aeration stone with CO2 in order to have the beer bubble and cap on foam. You made a comment that "it seems legit".

A doubt was raised in that thread, that the volume of the aeration stone, once extracted from the beer, would create an empty space on the bottleneck.

Still I want to make an attempt at it, maybe by immersing in the beer only a part of the aeration stone. I have a hunch that it might work, but cannot say until I try.

I have received my 0,2 micron aeration stone from China only a few days ago and I could only test it to oxygenate a "sugar wash" for distilling purposes. Besides, the test was not very encouraging because the oxygen came immediately on top and bursted, because sugar washes have no proteins to make a foam. Yet, I had the suspect that the stone which was sent to me was not 0,2 micron (used with cylinders) but 5 microns (used with aquarium pumps).

Aeration stone? Why unnecessary
overcomplicating this. Just use a thin silicon hose, dip it into the beer, just underneath the surface, start the co2 flow, cap on the foam!

 

[Birrofilo]

Aeration stone? Why unnecessary
overcomplicating this. Just use a thin silicon hose, dip it into the beer, just underneath the surface, start the co2 flow, cap on the foam!

I tried with the silicon hose immersed in the beer but I did not like the result. If memory serves, bubbles were too large and bursted immediately and formed no sufficient foam. So I just blowed the gas inside the bottle neck.
With an aeration stone the bubbles are tiny and they should foam better.

 

[Miraculix]

I tried with the silicon hose immersed in the beer but I did not like the result. If memory serves, bubbles were too large and bursted immediately and formed no sufficient foam. So I just blowed the gas inside the bottle neck.
With an aeration stone the bubbles are tiny and they should foam better.

Maybe the hose was too big?

 

[Birrofilo]

Maybe the hose was too big?

It's 3 mm internal diameter, the silicon hose which I posted in an answer to your question in anothe thread.

https://www.amazon.it/gp/product/B07R17LY8V/ref=ppx_yo_dt_b_asin_title_o01_s00
One could fit this other hose, which has an external diameter of 3mm and an internal diameter of 1mm into it.
https://www.amazon.it/sourcing-map-silicone-flessibile-Trasparente/dp/B07QD4TTY4/ref=sr_1_4
Then you fit this other silicon hose inside the other, restricting the hose to 0,5mm internal diameter

https://www.amazon.it/sourcing-map-silicone-flessibile-trasparente/dp/B07R2BQMYS/ref=sr_1_1_sspa
It's actually something worth trying if the aeration stone doesn't work.