Author Topic: Using collapsable bags to displace o2 during racking/packaging  (Read 2614 times)

Offline Bilsch

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #30 on: June 19, 2021, 04:32:24 pm »
Actually oxygen is quite soluble in water/beer...
This is not correct. Oxygen is not very soluble at all. It's ~40 times less soluble than CO2 and only about twice as soluble as N2--itself being, for the most part, insoluble. Like N2, O2 is a non-polar solute trying to be dissolved in a polar solvent. That said, O2 makes a difference for better and for worse in very small amounts. Maybe this is why everyone thinks it's so soluble. But it's not.

Very or not very makes no difference in this instance as it only takes PPB to damage your beer. And what do you think the O2 does when it gets into the beer, sit there and do nothing? No it reacts with the antioxidants (your fresh beer flavor) and makes room for more oxygen. It really wouldn’t matter if the solubility limit was 100 PPB or 100 PPM because the limit will never be reached due to consumption. Your argument here is a non sequitor.

The speed is relative to the concentration gradient. If there is little or no DO in your beer then the force to push it in there will be greater.
Also incorrect. If there is little or no DO in the beer, it won't take anything to add oxygen. The rate of dissolution will be rapid at first but will slow down tremendously as you approach equilibrium with the atmospheric concentration. It will slow down so much that it will be almost impossible to reach atmospheric concentration (but you'll get close). This is the same reason why chilling the wort happens so rapidly at first but slows down as you approach your groundwater temp. The first ~130 degrees of chilling happen in a few minutes but the final 20 degrees takes forever. So it is with O2 dissolution. The 2nd law of thermodynamics is a real b**ch.

Did you happen to read what I wrote? You simply disagreed with my statement and then went ahead and said the same thing. But hey.. I’m glad we finally got that settled. ;)

Concentration gradient is also germane to the polymer CO2 bag idea being discussed in this thread. Since all plastics are oxygen permeable to a certain extent, some much more than others, this idea won’t protect your beer from oxidation or staling.
Reality kicks theory's butt on this one.

That is your answer?
How have you measured your reality?

Oxygen is not very soluble in liquid. In the 15-ish minutes it takes to fill my keg, I doubt enough oxygen has dissolved in the beer to the point where it has seeped below the top ~1 inch of beer in the fermenter. IOW, I doubt that the beer that actually gets into the keg has any oxygen in it due to the open transfer.

I’m glad you based your belief on solid scientific evidence like your doubts.
Instead of guessing, I measure.
For example: I recently did a study on the oxygen permeability of the silicone hoses in my system and found that for 0.75” id x 0.5” od silicone hose,  a permeability of 0.0386ppm per hour, per inch of length.  I also re-ran the experiment with a barrier polymer wrap on the outside of the same hose and reduced that number to 0.0203ppm per hour, per inch of length. 


https://ibb.co/gSW9qkX
« Last Edit: June 19, 2021, 04:39:48 pm by Bilsch »

Offline Bilsch

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #31 on: June 19, 2021, 04:50:37 pm »
Hey Blisch -- tell you what. I'll fill that bag with Co2 and let you inhale it. Then you tell me how much Co2 you think is in it. ;) It definitely displaces the fermenter with Co2 when used as I suggedsted.

Yeah, eventually that collapsable bag will exchange o2. Though these are extremely sturdy bags. They aren't exchanging o2 over the 1-2 hours I'm using them.

I'm guessing you either didn't entirely read the purpose I proposed or you are fixated my suggesting they could be a way to capture Co2 for bottle conditioners or secodnary users without acess to Co2. I still think they could be used for this as well. I think they will exchange very little gas in that period.

How about instead of inhaling and guessing we use the proper instrument to determine if that is the case or not? Sturdy.. is that a good rating of the O2 permeability of plastic? I read exactly what you posted and I am telling you that oxygen will get through your sturdy bag and into the headspace of your jar. Believe it or not.
« Last Edit: June 19, 2021, 04:53:50 pm by Bilsch »

Offline majorvices

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #32 on: June 19, 2021, 06:00:35 pm »
Hey Blisch -- tell you what. I'll fill that bag with Co2 and let you inhale it. Then you tell me how much Co2 you think is in it. ;) It definitely displaces the fermenter with Co2 when used as I suggedsted.

Yeah, eventually that collapsable bag will exchange o2. Though these are extremely sturdy bags. They aren't exchanging o2 over the 1-2 hours I'm using them.

I'm guessing you either didn't entirely read the purpose I proposed or you are fixated my suggesting they could be a way to capture Co2 for bottle conditioners or secodnary users without acess to Co2. I still think they could be used for this as well. I think they will exchange very little gas in that period.

How about instead of inhaling and guessing we use the proper instrument to determine if that is the case or not? Sturdy.. is that a good rating of the O2 permeability of plastic? I read exactly what you posted and I am telling you that oxygen will get through your sturdy bag and into the headspace of your jar. Believe it or not.


If I fill a collapsable bag (please view the particular one I posted, I'm not talking about a WalMart shopping bag) with Co2 ... it's going to be filled with Co2 for all intents and purposes. This is a laughable argument. And I'm the one who should be laughed at most for arguing about it when this really just feels like an attempt to troll for no other reason but to troll.

Offline Bilsch

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #33 on: June 19, 2021, 08:14:15 pm »
If I fill a collapsable bag (please view the particular one I posted, I'm not talking about a WalMart shopping bag) with Co2 ... it's going to be filled with Co2 for all intents and purposes. This is a laughable argument. And I'm the one who should be laughed at most for arguing about it when this really just feels like an attempt to troll for no other reason but to troll.

So when someone comes here with alternate viewpoint that questions the efficacy of your clever ideas it's trolling? My apologies. Apparently the bubble here at this forum is made from a science barrier polymer?

On the bright side though there has been progress. If say three or four years ago someone postulated that you should attempt keep the headspace of your still beer protected from oxidation by using a CO2 filled bag.. heads would have exploded.

Offline majorvices

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #34 on: June 19, 2021, 08:58:12 pm »
Yawn. Go away, Bryan. I am certain you can find something better to do than this. Go do something productive. Trolling is so beneath you.

Offline tommymorris

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Using collapsable bags to displace o2 during racking/packaging
« Reply #35 on: June 19, 2021, 09:08:55 pm »
Back to the original post. I am doing that. My bag is smaller. During fermentation it fills with CO2. I then use it just like you have pictured when draining the fermenter into the keg. The only problem is, the bag probably had O2 in it before fermentation. I assume that O2 is still in there.

Here is a picture of mine waiting to be kegged.



PS. I don’t add the bag until the beer is a few points from terminal gravity. I still have to let lots of CO2 out. It fills up fast.
« Last Edit: June 19, 2021, 09:10:41 pm by tommymorris »

Offline majorvices

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #36 on: June 20, 2021, 06:04:48 am »
Tommy -- the ones I posted are completely collapsable. When they are devoid of air they lay completely flat. In fact, the lowest tech way I have found to make them completely void of air is just to suck on them, then sani the tube.

https://www.usplastic.com/catalog/item.aspx?itemid=122655
https://www.usplastic.com/catalog/item.aspx?itemid=136411



« Last Edit: June 20, 2021, 06:33:18 am by majorvices »

Offline tommymorris

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #37 on: June 20, 2021, 07:12:58 am »
Tommy -- the ones I posted are completely collapsable. When they are devoid of air they lay completely flat. In fact, the lowest tech way I have found to make them completely void of air is just to suck on them, then sani the tube.

https://www.usplastic.com/catalog/item.aspx?itemid=122655
https://www.usplastic.com/catalog/item.aspx?itemid=136411


Mine maybe completely collapsable also. I haven’t tried sucking the air out. I’ll try that next time.

Offline Richard

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #38 on: June 21, 2021, 09:37:35 am »
Aluminized mylar, like in a party balloon, has very low permeability for all gases (even helium). I use them for anti-suckback during cold crash, and they hold enough gas for that. The balloon can be folded flat and rolled to get almost all the air out at the start. The balloon is in place for days, so I use stainless steel tubing and double-wall EVA barrier tubing to reduce any oxygen coming in through the connection hoses. The balloons are small and it would take several to hold a 5 gallon keg's worth of gas for closed transfers, but it could be done. For a small fermenter, as in the photo for the original post, the balloon should be big enough. I use a keg instead, and use the fermentation gas to purge it. That kills two birds with one stone.
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Offline majorvices

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #39 on: June 21, 2021, 11:34:44 am »
Yep, the mylar is absolutely a better solution for long term storage. Definitely why hops are better stored in them. I just don't think that for this application it would make that much difference. Definitely a great option for "suck back" though.

Offline tommymorris

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #40 on: June 21, 2021, 09:18:58 pm »
Here’s your Mylar bag. Brew one of these and then rinse and keep the bag for capturing CO2.  The bag comes with 25 beers

https://www.maltwerks.com/brewery-in-a-bag

Offline hmbrw4life

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #41 on: June 22, 2021, 08:40:01 am »
Yawn. Go away, Bryan. I am certain you can find something better to do than this. Go do something productive. Trolling is so beneath you.


Bilsch is very well known around homebrew circles, and is not Bryan. I am not sure why there always has to be pot shots taken at folks who can't even respond. It's very petty.

Bilsch also has the tools necessary to back up his claims, I'd at least entertain them, since, all else at this point is speculation.
Science functions when theory correctly predicts the results of experiments.
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Offline hmbrw4life

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #42 on: June 22, 2021, 08:46:33 am »
Here’s your Mylar bag. Brew one of these and then rinse and keep the bag for capturing CO2.  The bag comes with 25 beers

https://www.maltwerks.com/brewery-in-a-bag

Oh that brings me back to homebrewing in the early 90's, *shudder*.
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Online denny

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #43 on: June 22, 2021, 09:32:24 am »
Yawn. Go away, Bryan. I am certain you can find something better to do than this. Go do something productive. Trolling is so beneath you.


Bilsch is very well known around homebrew circles, and is not Bryan. I am not sure why there always has to be pot shots taken at folks who can't even respond. It's very petty.

Bilsch also has the tools necessary to back up his claims, I'd at least entertain them, since, all else at this point is speculation.

The outcome of the beer is not speculation. That's the best way to judge effectiveness of any process.
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Offline hmbrw4life

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Re: Using collapsable bags to displace o2 during racking/packaging
« Reply #44 on: June 22, 2021, 10:10:04 am »
Yawn. Go away, Bryan. I am certain you can find something better to do than this. Go do something productive. Trolling is so beneath you.


Bilsch is very well known around homebrew circles, and is not Bryan. I am not sure why there always has to be pot shots taken at folks who can't even respond. It's very petty.

Bilsch also has the tools necessary to back up his claims, I'd at least entertain them, since, all else at this point is speculation.

The outcome of the beer is not speculation. That's the best way to judge effectiveness of any process.

Outcome of beer does not change the o2 permeation of polymers, or change the properties of the ideal gas laws. It's not the proper argument to make.
The speculation of folks without the tools to measure, is just that.

The argument to make is.. Does this bag method subjectively improve the beers for the people who use it?
If so, great!
If not, great!
Both are data points and we log those to make our decisions in the future.

None of which changes said properties above. FWIW I asked way back in this thread if he thought it made a difference, which is the question to ask since we are all are here to take people's experiences to choose if we want to follow or not.

Science functions when theory correctly predicts the results of experiments.
Six Sigma in a former life. Retired in the current life.