Purging headspace when bottling

[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.

 

[BrewnWKopperKat]

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

@Taket_al_Tauro - here are links to what I found in my notes.

/r/homebrewing
Actually, you can bottle NEIPAs at home ...
Tips to bottle a hazy/new England IPA with minimizing oxidation?
Tired of carbonation issues when bottling? Try dosing your bottles with ...
I did it. I bottled my first brew!
Individual bottle priming using sugar solution: ...
Very happy with how my Bottle Filler turned out

HomeBrewTalk
How to bottle NEIPA (without kegging)
Limiting oxidation: effect of purging headspace O2 in a bottle conditioned IPA
Limiting oxidation: effect of purging headspace O2 in a bottle conditioned IPA
NEIPA Bottle Oxidation and alternatives?
Purging headspace when bottling
A thought experiment for reducing oxygen naturally when bottling

AHA Forums
Topic drifted into bottling - the links in reply 29 may be of interest

eta: list created based on bookmarks on or before 2/4/2021 0:00 UTC

eta (2/8 4:30 et)
Bottling tips

 

[Taket_al_Tauro]

@Taket_al_Tauro - here are links to what I found in my notes.

/r/homebrewing
Actually, you can bottle NEIPAs at home ...
Tips to bottle a hazy/new England IPA with minimizing oxidation?
Tired of carbonation issues when bottling? Try dosing your bottles with ...
I did it. I bottled my first brew!
Individual bottle priming using sugar solution: ...
Very happy with how my Bottle Filler turned out

HomeBrewTalk
How to bottle NEIPA (without kegging)
Limiting oxidation: effect of purging headspace O2 in a bottle conditioned IPA
Limiting oxidation: effect of purging headspace O2 in a bottle conditioned IPA
NEIPA Bottle Oxidation and alternatives?
Purging headspace when bottling
A thought experiment for reducing oxygen naturally when bottling

AHA Forums
Topic drifted into bottling - the links in reply 29 may be of interest

eta: list created based on bookmarks on or before 2/4/2021 0:00 UTC

Thanks a lot!!
Most of these I already came across, but a couple I did not find yet, and are surely worth exploring. Cheers!

 

[neale]

I have been reading these threads with interest as I have just bottled my first NEIPA. Prior to deciding to brew a NEIPA I wasn't aware they where so sensitive to oxidation so hadn't intended on doing anything different to how a usually bottle. Which just involves a filling stick and bottle caps, no purging, shaking or anything else. I don't have any access to CO2 or kegs so most of the suggestions above are not an option for me.

But since I was reading all these threads while fermenting I figured I needed to do something quick so I opted to get some oxygen scavenging caps and reduce the headspace remaining in the bottles when filling. So that is what I did. But my reason for posting is that I have filled 3 clear bottles so I can monitor what happens over time without opening them. I have seen that a few people have done similar tests before but I don't think its been done with oxygen scavenging caps.

I have filled one bottle as I usually would and capped with a normal cap, one bottle filled as normal and capped with oxygen scavenging cap, and one bottle filled to a few mm from the top and then capped with oxygen scavenging cap. I have photographed the bottles and will check them from time to time to see if I get any differences.

I have started another thread at the following link

Oxygen Scavenging bottle cap test

For the record, regarding the co2 purging discussion, I think that if there is a way to achieve co2 bubbles successfully in each bottle, and the bubbles fill all the way to the top of the bottle then this in my unscientific opinion has to be the most likely to reduce oxygen levels. But if fancy caps can achieve the same thing its got to be easier......

 

[Silver_Is_Money]

If you plan to consume all of your beer within about 3 to perhaps 4 months max, then bottling it in an oxygen barrier equipped amber PET bottle which has been squeezed whereby to fill the bottle to a bit over completely full before simultaneously screwing on the cap will remove all headspace oxygen.

 

[BrewnWKopperKat]

I have started another thread at the following link

I saw the post & "bookmarked"/"followed" it. I'm looking forward to reading what you find.

I see that some discussion has already started in that topic. You may want/need to start a new topic with before / after posts when you have new information.

 

[BrewnWKopperKat]

If you plan to consume all of your beer within about 3 to perhaps 4 months max, then bottling it in an oxygen barrier equipped amber PET bottle which has been squeezed whereby to fill the bottle to a bit over completely full before simultaneously screwing on the cap will remove all headspace oxygen.

Do you have a recommended source for those bottles?

 

[Silver_Is_Money]

Do you have a recommended source for those bottles?

Coopers, or Mr. Beer if you are in the USA. When Coopers amber oxygen barrier PET beer bottles seemed to suddenly vanish in the USA, I emailed Coopers to ask them when/if they would be returning to this market, and they directed me to Mr. Beer. Try amazon.com perhaps.

Mind you, I haven't tried this personally (yet) but there is a YouTube video where a guy did this and got just about as good a result for his IPA as for purged keg beer. The PET bottled IPA stayed yellow while the glass bottled beer turned a yucky brown. I've heard that all such bottles are somewhat flimsy, but the 740 mL version is 'reportedly' a bit more robust than the 500 mL version.

 

[BrewnWKopperKat]

Coopers, or Mr. Beer if you are in the USA. When Coopers amber oxygen barrier PET beer bottles seemed to suddenly vanish in the USA, I emailed Coopers to ask them when/if they would be returning to this market, and they directed me to Mr. Beer. Try amazon.com perhaps.

Thanks.

 

[Silver_Is_Money]

There will always be oxygen ingress with PET bottles, even if they have an oxygen barrier. That said, if glass bottled turns brown in about 2 weeks (as has happened to me with IPA's), and it takes 3-4 months to arrive at the same fate with PET, then.... Even 2 months vs. 2 weeks would be an improvement.

 

[Silver_Is_Money]

The drawbacks for me (that have been holding me back) are the outrageous cost and 500 mL or 740 mL vs. 330 mL or ~355 mL (12 Oz.).