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Upgrading kegerator to duotight/evabarrier questions

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TandemTails

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I'd like to get away from the normal plastic hoses and upgrade to the evabarrier system. I was planning on starting with the CO2 lines since it wouldn't require disassembling the tower on my kegerator.

The problem is I'm not sure what fittings I'd need to attach to my regulator. I have one of these: https://www.amazon.com/gp/product/B0060NOX40/ with the barb fittings. I don't see any kind of duotight attachment for barbs and I'm not sure what thread size I'd need if i took the barbs off.

Has anyone successfully upgraded their co2 lines to this system? More info on it here: https://www.morebeer.com/category/duotight-evabarrier.html
 

Robert65

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I've done it. Those barbs on a Taprite thread into the body, there's a 1/4 MPT on them. You can unscrew them and replace them with the Duotight 1/4 MPT x PTC adapter.

https://www.morebeer.com/products/duotight-pushin-fitting-8-mm-516-14-mpt.html

Has a seated gasket which makes a very good seal.

If you want a shutoff (in place of one integrated into the barb on the Taprite) there's a separate Duotight ball valve, and check valve also.
 

day_trippr

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That regulator has 5/16" barbs on the shutoffs. While you could probably heat and stretch the 4mm ID tubing using a swaging tool and a hair dryer or hot water, I recommend using the 5mm ID/8mm OD EVAbarrier tubing for those barbs...

Cheers!
 
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TandemTails

TandemTails

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Thanks everyone! I'll go the route of unscrewing the barbs and get that 1/4 MPT adapter.
 

Carolina_Matt

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Thanks for asking the question! I had wondered the same thing, since there didn't seem to be any fittings that go over the barbs. I was completely unaware that the barbs were screwed on, and you can just take them off and use a 1/4" fitting.
 

MikeCo

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I've done it. Those barbs on a Taprite thread into the body, there's a 1/4 MPT on them. You can unscrew them and replace them with the Duotight 1/4 MPT x PTC adapter.

https://www.morebeer.com/products/duotight-pushin-fitting-8-mm-516-14-mpt.html

Has a seated gasket which makes a very good seal.

If you want a shutoff (in place of one integrated into the barb on the Taprite) there's a separate Duotight ball valve, and check valve also.
I'm planning on switching my gas lines to EVABarrier with DuoTight fittings also. If I already have MFL fittings on my regulator, am I better off just getting the same flare fittings for the regulator as I use for the QDs, or does the 1/4 MPT x PTC adapter offer some advantage?

Also - does location of check valves matter - closer to the keg or closer to the regulator?
 

Robert65

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I'm planning on switching my gas lines to EVABarrier with DuoTight fittings also. If I already have MFL fittings on my regulator, am I better off just getting the same flare fittings for the regulator as I use for the QDs, or does the 1/4 MPT x PTC adapter offer some advantage?

Also - does location of check valves matter - closer to the keg or closer to the regulator?
If you already have MFL fittings on a regulator or manifold, lucky you, just use the same connector as on the QD. I had barbs so had to replace them. As for position of the check valve, good question. I just put mine up by the regulator because, well, that's where it was by default before I redid the system. Maybe someone has a good line of reasoning on this.
 

Yesfan

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I've done it. Those barbs on a Taprite thread into the body, there's a 1/4 MPT on them. You can unscrew them and replace them with the Duotight 1/4 MPT x PTC adapter.

https://www.morebeer.com/products/duotight-pushin-fitting-8-mm-516-14-mpt.html

Has a seated gasket which makes a very good seal.

If you want a shutoff (in place of one integrated into the barb on the Taprite) there's a separate Duotight ball valve, and check valve also.
That's exactly what I'm looking for, for my regulator. Thanks!
 

GRBC

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Just be careful not to over tighten the duotight 1/4 MPT x PTC fitting into the regulator fitting where the barb was. Ask me how I know...
 

Holden Caulfield

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Just upgraded my keezer to duotight and ran into the same question.

The barb is part of the shutoff check valve and I was unable unscrew the barb from the check valve, so I jury rigged with picture below as a quick fix. Basically, it is the 3/8" barb to very short 5/16" gas line to 3/8" barb with 1/4" flare nut to 1/4" x 1/4" MFL connector (available at home depot) to duotight connector. It works fine but has a few more connections that could leak.

My future plan is to remove the entire check valve from regulator and replace it with one like this...


Probably can find a non-branded one cheaper. You can then attach a standard duotight flare connector to it. This will enable you to retain the shutoff check valve capability if important to you.

1597516742533.png
1597516843205.png


1597516800344.png
 

day_trippr

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Yeah, that price is the reason I didn't upgrade my 6-way manifold - or the three of my six regulators - from barbs to flare.
I just pushed 5mm ID EVAbarrier over the barbs and called it done...

Cheers!
 

Gozie Boy

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Just upgraded my keezer to duotight and ran into the same question.

The barb is part of the shutoff check valve and I was unable unscrew the barb from the check valve, so I jury rigged with picture below as a quick fix. Basically, it is the 3/8" barb to very short 5/16" gas line to 3/8" barb with 1/4" flare nut to 1/4" x 1/4" MFL connector (available at home depot) to duotight connector. It works fine but has a few more connections that could leak.

My future plan is to remove the entire check valve from regulator and replace it with one like this...


Probably can find a non-branded one cheaper. You can then attach a standard duotight flare connector to it. This will enable you to retain the shutoff check valve capability if important to you.

View attachment 694051View attachment 694053

View attachment 694052
Ouch! An equivalent shutoff with check valve can be found at Brewhardware for $9 (plus shipping). Buy a few other things (like you always need), and the shipping is effectively reduced. Even if bought stand alone (with full shipping) it's a much better deal at BH.
 

whovous

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Does size matter? I've always used 5/16" inside diameter hose for CO2. 5/16" is just under 8mm. The Evabarrier hoses have IDs of 4mm and 5mm. Does this matter? Also, is there any difference in strength between the Evabarrier and the typical silicone 5/16" ID hose? I assume that none of this matters, but would like some reassurance on this score.

I want to keep the CO2 canister outside of the mini-fridge I am about to convert. Should I drill a hole a little larger than the 8mm OD and then seal around it, or should I drill it a little smaller and rely on friction for the seal? I do not have metric drill bits, so going with exactly 8mm seems not be an option.
 

Holden Caulfield

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Does size matter? I've always used 5/16" inside diameter hose for CO2. 5/16" is just under 8mm. The Evabarrier hoses have IDs of 4mm and 5mm. Does this matter? Also, is there any difference in strength between the Evabarrier and the typical silicone 5/16" ID hose? I assume that none of this matters, but would like some reassurance on this score.

I want to keep the CO2 canister outside of the mini-fridge I am about to convert. Should I drill a hole a little larger than the 8mm OD and then seal around it, or should I drill it a little smaller and rely on friction for the seal? I do not have metric drill bits, so going with exactly 8mm seems not be an option.
I switched to 5mm ID EVA for CO2- works great.
 

day_trippr

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Old school gas tubing was always much larger than the 3/16" ID beer lines most of us use. I don't know why that was save that maybe it was to keep from mixing up fittings during fabrication of beer and gas lines (though now that I wrote that it seems unlikely).

I used the 5mm ID for all my gas lines only because of that barbed manifold and regs. I used almost three rolls just for the gas stuff (the three fridges, keezer, and then the fermentation-CO2 capture/purge rig I installed) so it made sense to be consistent...

Cheers!
 

GRBC

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I used 4mm for both beer & gas. Seemed easier to only have one size of ptc fittings.
 

day_trippr

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The PTC fittings are identical for 4mm and 5mm IDs...

Cheers!
 

Ihop2many

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Old school gas tubing was always much larger than the 3/16" ID beer lines most of us use. I don't know why that was save that maybe it was to keep from mixing up fittings during fabrication of beer and gas lines (though now that I wrote that it seems unlikely).
I think you'll find that 3/16" lines are used for beer, in our short-run home setups, as they have a higher restriction impedance over larger diameters. This is all down to "balancing" the flow with carbonation level. If 5/16" ID beer lines were used the run would need to be much longer, wasting beer, otherwise the beer would flow too quickly from the tap.

Cheers.
 

day_trippr

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Yeah, thanks, you're new here so unaware I've likely written a novel on HBT about balancing dispensing systems over the years :)
But how do you explain the 5/16" gas line? What was the point there?

Cheers!
 

Bobby_M

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I have to believe that the use of 5/16" or even 3/8" ID lines in some cases just caught on as a standard based on happenstance and no science at all. What's even more infuriating is when a customer calls looking for red or blue 5/16" ID tubing. Why would you want an opaque gas line so that if you have an unfortunate backup of beer into them, you won't see it? Even after explaining that smaller ID is more manageable, and clear is more practical, they insist on the big stupid bulky colorful (oxygen porous) stuff.


4mm ID is plenty big to push gas into the kegs.
 

day_trippr

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Totally agree - before I went to EVAbarrier I used the same 3/16" clear Bevlex 200 as I used for the beer lines...

Cheers!
 

fun4stuff

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I have to believe that the use of 5/16" or even 3/8" ID lines in some cases just caught on as a standard based on happenstance and no science at all. What's even more infuriating is when a customer calls looking for red or blue 5/16" ID tubing. Why would you want an opaque gas line so that if you have an unfortunate backup of beer into them, you won't see it? Even after explaining that smaller ID is more manageable, and clear is more practical, they insist on the big stupid bulky colorful (oxygen porous) stuff.


4mm ID is plenty big to push gas into the kegs.
Is there science to show a significant oxygen gets in through Standard oxygen porous gas tubing? I’d think diffusion across plastic tubing would be Slowed down since there is co2 under pressure.

Similar to fick’s law. Fick's Law | Pathway Medicine
“ Fick's Law essentially states that the rate of diffusion of a gas across a permeable membrane is determined by the chemical nature of the membrane itself, the surface area of the membrane, the partial pressure gradient of the gas across the membrane, and the thickness of the membrane.”
 

day_trippr

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CO2 pressure inside the tubing won't affect the rate of infusion of other gases....

Cheers!
 

whovous

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I have to believe that the use of 5/16" or even 3/8" ID lines in some cases just caught on as a standard based on happenstance and no science at all. What's even more infuriating is when a customer calls looking for red or blue 5/16" ID tubing. Why would you want an opaque gas line so that if you have an unfortunate backup of beer into them, you won't see it? Even after explaining that smaller ID is more manageable, and clear is more practical, they insist on the big stupid bulky colorful (oxygen porous) stuff.


4mm ID is plenty big to push gas into the kegs.
Oh c'mon, Bobby. Bright red silicone tubing is a whole lot prettier than EVA. More flexible, too. I plan to switch just as soon as I get the holes drilled in my next kegerator, but it won't be as pretty as it is now.

Bit serially, you make a good point. It seems the main reason we use the red tubing is that we have always done it that way.
 

day_trippr

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fwiw, EVAbarrier 8mm OD tubing will easily handle a ~1-1/2" bend radius...

tower_mods_10sm.jpg


Cheers!
 

fun4stuff

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CO2 pressure inside the tubing won't affect the rate of infusion of other gases....

Cheers!
According to fick’s law it does. It makes intuitive sense since things tend to follow concentration and pressure gradients.
 

Gozie Boy

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According to fick’s law it does. It makes intuitive sense since things tend to follow concentration and pressure gradients.
I don't follow. CO2 pressure inside the tubing means that there will be some CO2 loss through a permeable tubing to the atmosphere. This is only a cost issue, but is negligible for the trivial volume of CO2 lost.

The partial pressure of O2 inside the tubing is essentially ZERO, and the partial pressure of O2 at sea level is 21% x 14.7 psia = 3.1 psia, which is thus the O2 gradient from outside the tubing into the tubing. Therefore, there is a propensity to have oxygen enter a permeable tubing -- even under high co2 pressure. Am I missing or misinterpreting something here?
 

Bobby_M

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Is there science to show a significant oxygen gets in through Standard oxygen porous gas tubing? I’d think diffusion across plastic tubing would be Slowed down since there is co2 under pressure.

Similar to fick’s law. Fick's Law | Pathway Medicine
“ Fick's Law essentially states that the rate of diffusion of a gas across a permeable membrane is determined by the chemical nature of the membrane itself, the surface area of the membrane, the partial pressure gradient of the gas across the membrane, and the thickness of the membrane.”
In both replies you demonstrate a misunderstanding of the nuances in the law. "of THE gas across membrane" rather than "any gas".. It means a particular gas's propensity to migrate is based on the pressure differential OF THAT GAS on either side of the membrane. That is to say, CO2 is on the inside and there is little to no oxygen in there. But there IS oxygen outside and that differential will cause migration.

The good news is that you don't have to take anyone's word for it or even spend time researching. Make up a 5 foot picnic tap line out of clear PVC tubing and out of EVA. Dispense beer through both and then leave them both disconnected but inside your kegerator for a few days. Then hook them both back up and dispense exactly 1 ounce of beer into cups through both lines. Taste them blindly and discover what we're talking about.
 

Vale71

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Similar to fick’s law. Fick's Law | Pathway Medicine
“ Fick's Law essentially states that the rate of diffusion of a gas across a permeable membrane is determined by the chemical nature of the membrane itself, the surface area of the membrane, the partial pressure gradient of the gas across the membrane, and the thickness of the membrane.”
No need to look for something similar as this is actually governed by Fick's law. I've highlighted the part you have missed and that is most relevant to the discussion.
 

Vale71

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I don't follow. CO2 pressure inside the tubing means that there will be some CO2 loss through a permeable tubing to the atmosphere. This is only a cost issue, but is negligible for the trivial volume of CO2 lost.

The partial pressure of O2 inside the tubing is essentially ZERO, and the partial pressure of O2 at sea level is 21% x 14.7 psia = 3.1 psia, which is thus the O2 gradient from outside the tubing into the tubing. Therefore, there is a propensity to have oxygen enter a permeable tubing -- even under high co2 pressure. Am I missing or misinterpreting something here?
Not at all. As a matter of fact you're spot on.

The CO2 loss could be an issue in packaging in case of prolonged storage (especially if stored warm, where both permeability and pressure are significantly increased) where the loss of carbonation could become noticeable. That's one more reason why keg gaskets are made of low-permeability rubber such as Buna or EPDM, both to prevent O2 ingress as well as avoiding significant carbonation loss.
 

Gozie Boy

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Not at all. As a matter of fact you're spot on.

The CO2 loss could be an issue in packaging in case of prolonged storage (especially if stored warm, where both permeability and pressure are significantly increased) where the loss of carbonation could become noticeable. That's one more reason why keg gaskets are made of low-permeability rubber such as Buna or EPDM, both to prevent O2 ingress as well as avoiding significant carbonation loss.
Good point about CO2 loss from the keg. The small diameter of EvaBarrier tubing (i.e. much less surface area), plus its inner liner, means that this product must have a much lower CO2 loss from the keg (at least relatively) versus, say, 5/16 vinyl tubing. [And, by the same reasoning, much lower O2 ingress.].

Having said that, I now often remove the disconnects from my kegs if my system will not be in use for a few days or more. All it took was one odd leak in the system (which had held firm for a couple of years) and a drained beer gas tank to keep me on guard. Turned out to be a flare swivel connection that worked itself just loose enough to leak (probably my fault for not having wrenched it tightly enough). I hope the DuoTight connects are a little more robust (and idiot proof!).
 

Yesfan

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..........The good news is that you don't have to take anyone's word for it or even spend time researching. Make up a 5 foot picnic tap line out of clear PVC tubing and out of EVA. Dispense beer through both and then leave them both disconnected but inside your kegerator for a few days. Then hook them both back up and dispense exactly 1 ounce of beer into cups through both lines. Taste them blindly and discover what we're talking about.

I can personally attest to this. When I made the switch to EVA, instead of using the picnic tap test I just hooked up a second keg of the same beer to a tap with the EVA line. Like with the old line, I flushed both lines of the first few ounces to get fresh beer from the keg. Took samples from both and noted they tasted the same. Both were good.

Then I did another taste a couple of days later but this time didn't flush the lines like I used to do with the PVC lines. The beer from the Bevflex line tasted awful, very stale like. The EVA line showed no change and tasted the same as the previous day.
 

fun4stuff

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In both replies you demonstrate a misunderstanding of the nuances in the law. "of THE gas across membrane" rather than "any gas".. It means a particular gas's propensity to migrate is based on the pressure differential OF THAT GAS on either side of the membrane. That is to say, CO2 is on the inside and there is little to no oxygen in there. But there IS oxygen outside and that differential will cause migration.

The good news is that you don't have to take anyone's word for it or even spend time researching. Make up a 5 foot picnic tap line out of clear PVC tubing and out of EVA. Dispense beer through both and then leave them both disconnected but inside your kegerator for a few days. Then hook them both back up and dispense exactly 1 ounce of beer into cups through both lines. Taste them blindly and discover what we're talking about.
Thanks for the clarification. Can always count on someone on an online forum to put you right if you say something wrong... Cunningham’s law.

I was not talking about whether oxygen gets the the beer side line. I switched to EVA awhile back after it came out and it definitely prevents oxidation of the beer that’s left in the line.

I was questioning the need to replace the gas side with Eva line to stop/slow down oxidation. Would the pressure of co2 in the tube slow down the the diffusion of oxygen into the tube and into the beer. But as you pointed out, there’s no oxygen (or very little) in the tubing so the concentration gradient would favor oxygen to flow into the tube... unless for the some reason the co2 pressure in the tube would slow down oxygen influx.

I’m still questioning whether high pressure of co2 would slow down the diffusion of oxygen into the gas side.
 
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day_trippr

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Stop wondering. There are actual gas laws that say one gas will ignore the partial pressure of another...

Cheers!
 

Vale71

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I was questioning the need to replace the gas side with Eva line to stop/slow down oxidation. Would the pressure of co2 in the tube slow down the the diffusion of oxygen into the tube and into the beer. But as you pointed out, there’s no oxygen (or very little) in the tubing so the concentration gradient would favor oxygen to flow into the tube... unless for the some reason the co2 pressure in the tube would slow down oxygen influx.
Except no such reason exists nor will it ever exist...

I’m still questioning whether high pressure of co2 would slow down the diffusion of oxygen into the gas side.
In that case feel free to do your own research and publish a peer-reviewed paper that contradicts the work that Adolf Fick did in 1855 and the scientific community will gladly accept it, because that is how science works. If you were to manage that you might even get on the fast track for a Nobel in Physics, trip to Sweden included.

Until you manage to pull that off all you're doing with your posts is flaunting your own stubborness and steady refusal to learn, which means that anybody who's tried to repeatedly point you in the right direction has just been wasting his/her time (myself included).
 

Bobby_M

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I was not talking about whether oxygen gets the the beer side line. I switched to EVA awhile back after it came out and it definitely prevents oxidation of the beer that’s left in the line.

I’m still questioning whether high pressure of co2 would slow down the diffusion of oxygen into the gas side.
There are a lot of true things in the world that are counterintuitive.

Now you know the truth and are still resistant. Ok, dont do it. Drink the slightly oxidized beer.
 
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