Closed Transfer: What About the Jumper Lines?

[AlexKay]

I'm trying to think through all the steps necessary to get the lowest possible oxygen exposure.

I'm planning to ferment in a corny keg. I'll use a jumper line from the gas post of the keg to the liquid post of another keg in order to purge the second keg of oxygen with fermentation CO2. The CO2 has to go somewhere, so there will be a jumper from the gas post of the second keg to a blow-off tube immersed in StarSan.

Jumper lines will be EVABarrier, because otherwise why bother? I'm considering SS lines but I'll probably decide this is too much trouble.

When it comes time for a closed transfer, though, things get trickier. I'm going to want a liquid-post-to-liquid-post jumper to transfer beer, and a gas-to-gas jumper to equalize CO2 pressures.

How am I supposed to flush the oxygen out of these jumper lines?

One option I can see is using a gas-to-gas jumper, a double-sided ball-lock post (like so), and a gas disconnect on a tube as the blow-off tube, and then popping off the gas-to-gas jumper, already purged with the fermentation CO2, and using it for the transfer. What about the liquid-to-liquid jumper line, though? Use a double-sided post and blow CO2 from the tank through it? This seems sub-optimal; I expect it to work well enough, but not get those uber-low residual O2 levels that I'd get from purging with fermentation gas. It seems overly complicated though maybe possible to use a gas-to-liquid jumper in series with a liquid-to-liquid jumper so that line gets purged with fermentation CO2 as well.

Am I overthinking this? Is permeability of the EVABarrier or the post O-rings, or leaks in the disconnects, an order of magnitude bigger than the so-to-speak problems I'm trying to solve? How do other folks do this?

 

[Broken Crow]

Here's what I use:

The bottle of Starsan was filled via the disconnect on the side and closed with it running over the top so it contains only Starsan & CO2...If left connected while sanitzing, I can flip it upside to purge.

 

[mac_1103]

Can't you just put QDs in all of the lines?

 

[day_trippr]

Don't make things harder than they need to be: don't daisy chain the kegs when filling...

Cheers!

 

[Bassman2003]

I have the keg hooked up to my spunding valve via the same gas transfer line through fermentation. So the fermenter gas purges the gas line. When I go to transfer, I use the same setup as shown above with the 2-liter bottle but without any liquid inside. I run a little bit of beer out of the fermenter into the 2-liter bottle and pull the disconnect mid-flow. So the liquid line is purged because it is full of beer. So with both lines O2 free I do the transfer.

 

[Cider Wraith]

Has the fermenter been pressurized with the use of a fermenting pressurizing valve? In any case the fermenter will need to be a couple PSI higher than the server. At any point you can boost fermenter pressure with a tank or reduce server pressure with the PRV, both functionally identically. Put the fermenter on a countertop and the server on the floor.

Construct two jumper lines with black-to-black and white-to-white. Connect a white QD to the fermenter (at higher than atmosphere pressure) and using your finger depress the poppet for a couple of seconds to purge the line with CO2 (if you really want to get picky, purge this line with liquid as described and then purge again with CO2 as described). Connect one black QD to the fermenter and hold the line above your head and using a finger depress a poppet until the line is completely filled with liquid and you get a few drops out. Complete the connection of black-to-black and the syphon will begin. Quickly before pressure differentials stop the syphon attach the other white and liquid will siphon into server on the floor with the space lost being replace with CO2 from the purged server.

 

[max9]

I’m assuming you’re serving ‘on tap’? Since you’re fermenting in Corny kegs, why not eliminate the blow off tube by putting on a spunding valve so as to ferment under pressure. Then serve on the lees. After the first couple pours the sediment is gone and you have beer that has not been exposed to ANY oxygen.

 

[AlexKay]

I’m assuming you’re serving ‘on tap’? Since you’re fermenting in Corny kegs, why not eliminate the blow off tube by putting on a spunding valve so as to ferment under pressure. Then serve on the lees. After the first couple pours the sediment is gone and you have beer that has not been exposed to ANY oxygen.

I have floating dip tubes ready to go, too! So do folks like this metal one, or this Duotight one, or something else?

 

[Dland]

Am I overthinking this? Is permeability of the EVABarrier or the post O-rings, or leaks in the disconnects, an order of magnitude bigger than the so-to-speak problems I'm trying to solve? How do other folks do this?

My take is you're overthinking it some, though I do understand the drive to achieve best possible results. The "law of diminishing returns" applies to O2 exclusion as it does most other things.

If you start with a purged and CO2 filled keg, which is going to be filled almost to the top with beer, the amount of O2 from line left in headspace is negligible.

But if you want to purge lines, simply blow them out from a empty keg that is purged and somewhat pressurized, but I would not bother.

 

[tracer bullet]

But if you want to purge lines, simply blow them out from a empty keg that is purged and somewhat pressurized, but I would not bother.

Basically what I do. I figure it works... I do a closed loop transfer to my keg from my fermenter. After I purge the keg, I keep a psi or so of pressure in it. Then when I attach my hoses, each sees a little burst of CO2 blow through.

 

[Bassman2003]

O2 ingress is a difficult conversation as it is more finite than many homebrewers want to deal with or can measure. But, nothing we can do is overkill when it comes to something measured in the parts per billion in final professional packaging.

EVA tubing as well as buna-N lid and O-ring seals as well as purging everything is the best we can do. Imho, EVA + purging is a must.

 

[AlexKay]

O2 ingress is a difficult conversation as it is more finite than many homebrewers want to deal with or can measure. But, nothing we can do is overkill when it comes to something measured in the parts per billion in final professional packaging.

EVA tubing as well as buna-N lid and O-ring seals as well as purging everything is the best we can do. Imho, EVA + purging is a must.

Huh. Are the o-rings that come with the kegs (and the disconnects) Buna already, or do you swap them. And why not Viton (other than cost, that is)?

 

[tracer bullet]

Interesting question. Historically I believe the black o-rings are buna and red are silicone. But then I have some white ones for the keg lids that must be silicone. That's not an official answer of course but historically is what I've seen when I've noticed a material actually be listed.

 

[Bassman2003]

To my understanding, nothing that comes on a corny is oxygen proof. I tend to be the only person drinking most of my beer, so the kegs sit on tap for months. I changed out all of the rubber bits to buna-N as it has the best O2 properties. EPDM is a lot better than silicone but buna-N is better than EPDM.

 

[Yesfan]

I have floating dip tubes ready to go, too! So do folks like this metal one, or this Duotight one, or something else?

For me, the Duotight spunding valve I like better. I have two DIY spunding valves that look like the ones in the Northern Brewer link, but I like the Duotight much better....and it's cheaper.

I made jumper lines with duotight and I put a duotight valve at the (keg) end for a shut off. When I purge my lines, I just use my spare co2 tank to flush the lines. Likewise, I flush the lines with a few ounces of beer too since I have the shut off valve.

If you get one of those disconnect jumpers, get the universal ones. The ones from Northern Brewer are beer only couplers. They won't work with the grey gas disconnects. @Bobby_M sells the universal couplers where you can connect beer to beer or gas to gas disconnects. That's where I got mine from. He also has a couple to where I can connect a beer line directly to my Chugger pump, which I use for recirculating cleaner, rinse water, sanitizer, etc.

 

[Broken Crow]

I'm fond of my duotight kegland spunding valve, but not for 'perfect' accuracy, nor as it ships... The disconnect that came with mine jams on posts, so I replaced it with a CM Becker, and the lines are too short and I want an end to reach a bottle or starsan.. also, there's those little blue retainer clips I added because this duotight unit isn't so tight, and if you bend the stock configuration, sometimes just under its own weight, it leaks.... Once those issues are addressed, though it's been serving me but cheaply and reliably for the last couple of years. When I want accuracy though, I'll buy the Blichmann.

 

[Yesfan]

I'm fond of my duotight kegland spunding valve, but not for 'perfect' accuracy, nor as it ships... The disconnect that came with mine jams on posts, so I replaced it with a CM Becker, and the lines are too short and I want an end to reach a bottle or starsan.. also, there's those little blue retainer clips I added because this duotight unit isn't so tight, and if you bend the stock configuration, sometimes just under its own weight, it leaks.... Once those issues are addressed, though it's been serving me but cheaply and reliably for the last couple of years. When I want accuracy though, I'll buy the Blichmann.

Same here about the Blichmann. I like the Spike one as well, and may lean in that direction for my 10 gallon fermenters.

 

[Dr_Jeff]

Don't make things harder than they need to be: don't daisy chain the kegs when filling...

Cheers!

That's what I do, brew 10 gallon batches, daisy chain the kegs together and start the fill process from the kegmenter with a spunding valve on the second keg.

 

[Dland]

O2 ingress is a difficult conversation as it is more finite than many homebrewers want to deal with or can measure. But, nothing we can do is overkill when it comes to something measured in the parts per billion in final professional packaging.

EVA tubing as well as buna-N lid and O-ring seals as well as purging everything is the best we can do. Imho, EVA + purging is a must.

Hi Bassman, I've been considering this thread since your post and have a few thoughts:

1, Agree keg purging is a must. It is also easy and free to do with fermantion gas. There is good info on how to do that on this site, for any new keggers looking at this thread.

2, How do things like keg O-ring material matter if there is always positive CO2 pressure out with a spunding or already carbonated keg?

3, Hopefully anyone looking to reduce post carbonation O2 exposure in kegs is spundng, as the small % of O2 in most CO2 tanks has more than parts per billion.

Let me know if you think I'm missing something, always willing to learn. But in consideration to fellow home brewers, don't want to send anyone down an O2 rabbit hole when the main cave entrance is open.

 

[AlexKay]

Hi Bassman, I've been considering this thread since your post and have a few thoughts:

1, Agree keg purging is a must. It is also easy and free to do with fermantion gas. There is good info on how to do that on this site, for any new keggers looking at this thread.

2, How do things like keg O-ring material matter if there is always positive CO2 pressure out with a spunding or already carbonated keg?

3, Hopefully anyone looking to reduce post carbonation O2 exposure in kegs is spundng, as the small % of O2 in most CO2 tanks has more than parts per billion.

Let me know if you think I'm missing something, always willing to learn. But in consideration to fellow home brewers, don't want to send anyone down an O2 rabbit hole when the main cave entrance is open.

2. I’ve had a few discussions on this point. Basic physics in the form of Fick’s law says that oxygen will diffuse in regardless of the presence of other gases. I’ve argued that there’s good reason that diffusion might be non-Fickian in this particular case, and so a positive pressure of CO2 might provide some protection. But it’s not a silly thing to worry about the o-rings, especially if they’re silicone.

3. A small proportion of oxygen in bottled CO2 may not be the end of the world. Gas specs will be in ppt/ppm/ppb by volume (number), while what you’re concerned about is ppb in solution by weight. Because gas is so diffuse, ppm of oxygen in a moderate head space leads to ppb of oxygen in solution. In many cases bottled CO2 won’t be a problem.

 

[Dland]

2. I’ve had a few discussions on this point. Basic physics in the form of Fick’s law says that oxygen will diffuse in regardless of the presence of other gases. I’ve argued that there’s good reason that diffusion might be non-Fickian in this particular case, and so a positive pressure of CO2 might provide some protection. But it’s not a silly thing to worry about the o-rings, especially if they’re silicone.

3. A small proportion of oxygen in bottled CO2 may not be the end of the world. Gas specs will be in ppt/ppm/ppb by volume (number), while what you’re concerned about is ppb in solution by weight. Because gas is so diffuse, ppm of oxygen in a moderate head space leads to ppb of oxygen in solution. In many cases bottled CO2 won’t be a problem.

2, how can gas diffuse in when there is 30 PSI pressure pushing out at 60F, 12 PSI or so at 33F?

3. if you are worried about O2 ingress against pressure out, which would be miniscule or less, one should consider the small % of O2 in bottled CO2. I've brewed around 80 two keg batches since I switched from forced carbing to keg spunding. I can defininatly tell the difference, especially in last 3rd of keg.

 

[AlexKay]

2, how can gas diffuse in when there is 30 PSI pressure pushing out at 60F, 12 PSI or so at 33F?

3. if you are worried about O2 ingress against pressure out, which would be miniscule or less, one should consider the small % of O2 in bottled CO2. I've brewed around 80 two keg batches since I switched from forced carbing to keg spunding. I can defininatly tell the difference, especially in last 3rd of keg.

2. The question is whether CO2 molecules interact with the O2 molecules. Simple models say they don't, and in many cases the simple models are right. I'm not 100% convinced that this particular system obeys Fick's law, but silicone is really porous, and getting it out of the system certainly won't hurt. I can tell you that professionals absolutely worry about permeability of plastics in both directions -- CO2 out and O2 in -- when they're looking at crown corks or PET bottles.

3. It depends how good your CO2 is. I've done back-of-the-envelope calculations, and the conversion is roughly 1 ppm by volume of gas goes to 1 ppb by weight in solution. And that's with lots of headspace; things are much better if your keg is near-full. When you say you could tell the difference, did you do a side-by-side blind tasting?

There's also a point to be made that fermentation doesn't just make CO2, and that some fermentation gases are pretty strongly flavor-negative ... H2S, for example. If you spund aggressively, you could be hurting things in one area more than you're helping them in another.

 

[Bassman2003]

Great exchange here. Yes, I agree with the sentiment of prioritizing steps for O2 exclusion in order of effectiveness etc... Here is my order/list:

1) Keg purging. This is the environment that beer will sit in for possible months. I used to drop a hose in, close it up and give a few tank CO2 blasts. One does things until they learn a better way. However one purges - filling with sanitizer and pushing out with tank CO2 or fermentation gas purging, this is the best we can do as homebrewers.

2) Closed Transfers. This is a close 2nd but not letting the beer touch atmosphere is very important. All lines must be purged and is possible, have a little active yeast in play to clean up after the transfer. If no active yeast then be extra careful as there is no cleanup crew.

3) EVA Barrier Tubing. This stuff is way better than the old Bevflex stuff and it costs less. It keeps the O2 out as the other line types let O2 in while your beer sits on tap.

4) Natural Carbonation / Spunding. This is 100% natural CO2 compared to something less of 100% with tank gas. It is free and imparts a really smooth carbonation. Spunding also goes well with pressure fermentation as you might even be at the desired CO2 volume during fermentation etc... Tank gas will stale your beer over time, no doubt.

5) Keg Seals. As discussed a few posts up, Oxygen permeates materials. Period. It does not matter what is on the other side, it finds it way in. Changing all of the seals to Buna-N is another way to put up a barrier that oxygen has a problem penetrating. With the standard seals, the O2 gets in and stales the beer over time. While this is a smaller amount, it still happens but is lower on the list.

I realize some of this seems like overkill or a bridge too far. I get it. I used to have the same opinion. But it does stop it from being a reality, just a reality that many hobby brewers do not want to grapple with. And I get that too. But it really does have an impact to consider this stuff over time, bit by bit. Since I have been studying oxygen mitigation for about four years in my own brewing, it is 2nd nature to want to protect all of the work on the hot side. But the choice is for everybody to make on their own.

 

[Dland]

3. It depends how good your CO2 is. I've done back-of-the-envelope calculations, and the conversion is roughly 1 ppm by volume of gas goes to 1 ppb by weight in solution. And that's with lots of headspace; things are much better if your keg is near-full. When you say you could tell the difference, did you do a side-by-side blind tasting?

There's also a point to be made that fermentation doesn't just make CO2, and that some fermentation gases are pretty strongly flavor-negative ... H2S, for example. If you spund aggressively, you could be hurting things in one area more than you're helping them in another.

My only source of CO2, other than what my fermentations generate, is local Airgas dealer. I doubt many have access to lab grade CO2, I sure don't, I live on an island. If what I've read on this forum is to be believed, commercial CO2 is often around only 99% pure. I'm not a math wiz, but doesn't that imply parts per thousand of non-CO2 gas? No doubt a lot of it O2?

I don't need blind testing to detect oxidation in my beer, been a conosur for decades. Heck, I have not had a commercial beer that has not been oxidized to some degree, now that I know what really fresh fresh tastes like. I'm sure there is some really fresh beer to be bought somewhere, but not where I'm at.

Not sure what spunding aggressively would entail, I shoot for 30 around PSI at 60F, seems to get initial carbonation to a level I enjoy for most brews.

A little off topic perhaps, but I have experimented with intentionally "over spunding" that is letting CO2 pressure get above 30PSI, then using extra gas, (which is in crashed keg in near keg being dispensed) as dispensing gas, and have detected no ill effects. Not that this is a regular practice, but perhaps any dissolved gas from fermentation other than CO2 dissipates on serving along with the carbonation. I'll let the theorists contemplate that one, but it is nice to know I have means to dispense beer without outside gas source if I have to.

 

[Dland]

Great exchange here. Yes, I agree with the sentiment of prioritizing steps for O2 exclusion in order of effectiveness etc... Here is my order/list:

1) Keg purging. This is the environment that beer will sit in for possible months. I used to drop a hose in, close it up and give a few tank CO2 blasts. One does things until they learn a better way. However one purges - filling with sanitizer and pushing out with tank CO2 or fermentation gas purging, this is the best we can do as homebrewers.

2) Closed Transfers. This is a close 2nd but not letting the beer touch atmosphere is very important. All lines must be purged and is possible, have a little active yeast in play to clean up after the transfer. If no active yeast then be extra careful as there is no cleanup crew.

3) EVA Barrier Tubing. This stuff is way better than the old Bevflex stuff and it costs less. It keeps the O2 out as the other line types let O2 in while your beer sits on tap.

4) Natural Carbonation / Spunding. This is 100% natural CO2 compared to something less of 100% with tank gas. It is free and imparts a really smooth carbonation. Spunding also goes well with pressure fermentation as you might even be at the desired CO2 volume during fermentation etc... Tank gas will stale your beer over time, no doubt.

5) Keg Seals. As discussed a few posts up, Oxygen permeates materials. Period. It does not matter what is on the other side, it finds it way in. Changing all of the seals to Buna-N is another way to put up a barrier that oxygen has a problem penetrating. With the standard seals, the O2 gets in and stales the beer over time. While this is a smaller amount, it still happens but is lower on the list.

I realize some of this seems like overkill or a bridge too far. I get it. I used to have the same opinion. But it does stop it from being a reality, just a reality that many hobby brewers do not want to grapple with. And I get that too. But it really does have an impact to consider this stuff over time, bit by bit. Since I have been studying oxygen mitigation for about four years in my own brewing, it is 2nd nature to want to protect all of the work on the hot side. But the choice is for everybody to make on their own.

I'm already there on 1, 2 and 4, and will look to use Buna-N seals next time I rebuild my keg fleet.

EVA tubing sounds good too, I should get some next time I repalce my lines, but as I dispense my brews from a 12 keg freezer and don't leave any kegs hooked up, lack of it has not affected my drinking experience. Also dispensing line is short as I use a pressure compensator rather than coils of tubing.

A bit off topic, but not using a proper keezer with beers permanently on tap or hooked to CO2 manifold reduces O2 ingress and eliminates chance of leakage. A pain, one might think, but I also keep my beer in building next door and down a flight of stairs, this does not keep me from enjoying more than I probably should be drinking, and helps keep me in shape too { : .

 

[mac_1103]

commercial CO2 is often around only 99% pure. I'm not a math wiz, but doesn't that imply parts per thousand of non-CO2 gas? No doubt a lot of it O2?

Food/beverage grade CO2 is supposed to be 99.9% pure, which implies one part per thousand, not all of it O2. Industrial/medical grade is 99.5%. Research grade is 99.999%, but who's going to pay for that even if they could get it?

According to these guys*, Beverage grade CO2 "typically has a maximum of 30 ppb O2 impurity depending on supplier." Now they go on to argue that this is too much and they do come down on the side of spunding for that reason, but then they say that it's OK to force carbonate if "you can verify your CO2 source is 99.9% pure (< 10 ppb O2 impurity) or greater." They don't comment on how you're supposed to know the difference between 99.9% / 30 ppb and 99.9% / 10 ppb. But you're still going to have an increasing volume of contaminating O2 in the head space as you serve, I guess you'd still better drink it fast.

*Edit: adding the link to that article failed three times; not sure why. So maybe I'll just insert it below and see if that works.

Edit 2: Obviously I'm breaking some rule, so I guess you'll have to google it yourselves. Title of the article is "CO2 purity and why it's important."

 

[tracer bullet]

how can gas diffuse in when there is 30 PSI pressure pushing out at 60F, 12 PSI or so at 33F?

I'm pretty sure about this, but an expert should chime in if there's one around...

You can have 12psi of CO2 in a line. And your line can be permeable by oxygen. And you have ambient air around with O2 in it.

Even if the ambient air pressure is far less than the CO2 pressure in the line, you will still get O2 going into the line, into the CO2 filled area.

The reason is because, strictly from the standpoint of the O2, there's some O2 outside of the line and therefore some O2 pressure outside of the line. But none inside the line. Lots of Co2 pressure inside, but no O2 pressure inside. And so the O2 will indeed permeate through the line and get inside until it balances out.

This is why EVA barrier lines for CO2 are helpful.

Partial pressures of gasses are pretty crazy, and yes I could be wrong on the above, but I'm fairly sure about it. Would love for an expert to say either way.

 

[Bassman2003]

@Dland, it sounds like you have already been doing this stuff for a while. The setup where you do not let lines sit hooked up to a serving keg is great for keeping O2 away. You would probably not benefit from EVA lines very much then. But, there is another gotcha - every time one connects a QD, there is a strong opportunity for O2 to creep in. There is an air pocket in the QD and when it is pushed on, that air pocket is right over the opening of the poppet. Many in the other community believe leaving the QD connected with EVA Barrier and Buna-N seals is better than disconnecting and connecting. Yes it is a rabbit hole

 

[AlexKay]

Food/beverage grade CO2 is supposed to be 99.9% pure, which implies one part per thousand, not all of it O2. Industrial/medical grade is 99.5%. Research grade is 99.999%, but who's going to pay for that even if they could get it?

According to these guys*, Beverage grade CO2 "typically has a maximum of 30 ppb O2 impurity depending on supplier." Now they go on to argue that this is too much and they do come down on the side of spunding for that reason, but then they say that it's OK to force carbonate if "you can verify your CO2 source is 99.9% pure (< 10 ppb O2 impurity) or greater." They don't comment on how you're supposed to know the difference between 99.9% / 30 ppb and 99.9% / 10 ppb. But you're still going to have an increasing volume of contaminating O2 in the head space as you serve, I guess you'd still better drink it fast.

*Edit: adding the link to that article failed three times; not sure why. So maybe I'll just insert it below and see if that works.

Edit 2: Obviously I'm breaking some rule, so I guess you'll have to google it yourselves. Title of the article is "CO2 purity and why it's important."

I had a look at the article (though not the 1985 reference they cite, which is behind a paywall.) The equation they are using is

Where DO2 is O2(aq) in ppb, x is supposed to be the ppb concentration (v/v) of oxygen in your CO2, and y is the volumes of CO2 to carbonate your beer.

Unless I'm missing something, that ten-to-the-minus-sixth in front means that x is instead the parts per million of oxygen in your CO2. So their conclusion stands, except 1000 times better: if your CO2 has a 30-ppm impurity, it's probably a good idea to spund. Significantly better than that and you're OK force-carbonating. If they're correct that beverage-grade CO2 has on the order of 30 ppb of O2, the amount of oxygen introduced in this way is measured in parts per trillion.

The bad news is that I have no idea where their 30 ppb number comes from. A little Googling instead gives 30 ppm as a value, though that's a maximum and not typical value.

 

[Bassman2003]

It is tough to know exactly, so experience comes into play. (This applies more to low oxygen brewed beers, but also applies to hop forward beers). I can definitely notice the beer start to drop off when it gets hooked up to the tank gas for serving. The flavors get rounded off, then go dull. Hop aroma and flavor fades etc... It just happens, so I have gotten past wanting to know the numbers.

 

[mac_1103]

I can definitely notice the beer start to drop off when it gets hooked up to the tank gas for serving.

How fast?

 

[mac_1103]

The bad news is that I have no idea where their 30 ppb number comes from. A little Googling instead gives 30 ppm as a typical value, though that's a maximum and not typical value.

Typo? The reference that they took the table from says ppm.

 

[Pacific Electric]

I use a double sided jumper to purge my transfer line with CO2. Then I ‘purge’ the line with beer from my fermenter, and discard a few ounces that might get a bit of O2 exposure. After that I connect to my keg and transfer, and hope it was enough.

 

[Dland]

Well, all this has got me thinking I ought to get EVA lines, especially for the one from gas tank to kegs. I picture it now sitting there coiled around the tank in the cellar, absorbing O2 and plotting to stale my beer...{ ; Good thing I tend to drink it pretty fast once tapped. .

A lot of things about brewing can be seen as rabbit holes, or can be seen as things that could be improved, even if only incrementally at some point. For me this is better than being content with the other extreme; making and drinking mediocre beer year after year...

How pure tanked CO2 probably varies, may not live up to published specs, and there's always plenty of room for quality control lapses at the bottling plant. Pretty sure what I get and lots of others get is industrial grade. The only gas in separate category from the different industrial/welding gas choices I have seen is the medical oxygen.

Maybe the CO2 that beverage distributors supply is beverage grade, it came from a different supply chain when I was in restaurant business. But no way would the Coca Cola dealer sell it to me now unless I was buying their soda syrup and leasing their dispensers.

So if one is in pursuit of quality enough to be worried about EVA lines and Buna-N seals, one also ought to consider spunding. Using gas from "over spunded" kegs to help dispense seems a good practice too, but will only get one so far.

 

[AlexKay]

Well, all this has got me thinking I ought to get EVA lines, especially for the one from gas tank to kegs. I picture it now sitting there coiled around the tank in the cellar, absorbing O2 and plotting to stale my beer...{ ; Good thing I tend to drink it pretty fast once tapped. .

There's a pretty universal consensus 'round these parts that EVA or other barrier tubing is necessary for liquid lines. Plenty of people will tell you it is necessary for gas lines, as well. My personal experience (anecdote does not equal data) is that PVC gas lines (and, for that matter, tank O2) don't cause a severe oxidation problem, at least as measured by my own taste and the taste of judges at competitions I enter, at least for non-hoppy beers.

So if one is in pursuit of quality enough to be worried about EVA lines and Buna-N seals, one also ought to consider spunding. Using gas from "over spunded" kegs to help dispense seems a good practice too, but will only get one so far.

I think this is a pretty fair statement. I just ordered a spunding valve because of this thread.

 

[Bassman2003]

I think over spunding is a good approach if you can pour successfully. EVA is cheap, so you might as well do both gas and liquid.

How fast does the downhill slide go? It is tough to say. Maybe 2-4 weeks the beer is a lesser percentage from when it started. These are gradual changes kind of like a frog in slowly rising temp water but the malt character goes to more sweet and the hop aroma fades away. The color goes darker too. Some styles this is not bad at all like a Scottish ale.

 

[Dland]

Just to be clear, when I over spund, the keg in question will be over carbed and pour that way, all foam. What I do is hook a jumper from gas post of over-spunded keg to gas post on another keg in freezer that is being dispensed. The over spunded beer is fresh and still lagering, but I get dispensing gas from it as it's carbonation is reduced to desired level. This works out as I typically have a pipeline of at least 12 kegs going most of the time. It does take some paying attention to, but most of us here are used to that regarding our beer.

 

[Yesfan]

Well, all this has got me thinking I ought to get EVA lines, especially for the one from gas tank to kegs. I picture it now sitting there coiled around the tank in the cellar, absorbing O2 and plotting to stale my beer...{ ; Good thing I tend to drink it pretty fast once tapped. .

A lot of things about brewing can be seen as rabbit holes, or can be seen as things that could be improved, even if only incrementally at some point. For me this is better than being content with the other extreme; making and drinking mediocre beer year after year...

How pure tanked CO2 probably varies, may not live up to published specs, and there's always plenty of room for quality control lapses at the bottling plant. Pretty sure what I get and lots of others get is industrial grade. The only gas in separate category from the different industrial/welding gas choices I have seen is the medical oxygen.

Maybe the CO2 that beverage distributors supply is beverage grade, it came from a different supply chain when I was in restaurant business. But no way would the Coca Cola dealer sell it to me now unless I was buying their soda syrup and leasing their dispensers.

So if one is in pursuit of quality enough to be worried about EVA lines and Buna-N seals, one also ought to consider spunding. Using gas from "over spunded" kegs to help dispense seems a good practice too, but will only get one so far.

From my own personal experience, I could tell the difference between EVA and PVC when I made the switch to EVA/Duotight. At the time of the switch, I had two kegs of the same beer (from a 10 gallon batch) so I decided to hook both to two open taps. One line had the recently cleaned/sanitized PVC Beverage line and the other the new EVA with Duotight push to connect style (like John Guest) fittings, which were also cleaned/sanitized.

In the past, I would always purge the beer in the beer line as those first few ounces in the line always tasted off. This was the biggest thing I noticed with the EVA. The beer in the EVA line after going a day without drinking tasted the same. Nothing off. So I changed both beer/gas line to EVA/Duotight.

Three other advantages of the EVA/Duotight line/fittings are:

1 The ability to use shorter runs of beer line without the worry of foamy pours. This is because of the smaller 4mm ID of the EVA line.

2 Cost. The EVA line is much cheaper than the more expensive Ultra barrier stuff I had been using.

3 PTC style fitting are easier to build lines vs dealing with MFL swivel nuts, otiker and/or worm gear clamps.

I've more or less replaced every kind of line with this stuff and not looked back.

 

[Biggz1313]

I have floating dip tubes ready to go, too! So do folks like this metal one, or this Duotight one, or something else?

I have multiple of the duotight ones and love them. I use them at the end of my daisy chain so CO2 from my All Rounder during fermentation is pushing Star San out of a keg that wall filled to the brim. That star san is being pushed into another empty cleaned all rounder and then the gas post for the star san all rounder has a spunding valve attached to it. that way i'm using fermentation co2 to purge my clean star san keg and not store bought CO2 and then my next fermenter is also being sanitized in the process and the starsan is kept in a CO2 only closed environment further extending it's shelf life.

edit: Duotight spunding valve is also super easy to clean.

 

[tracer bullet]

In the past, I would always purge the beer in the beer line as those first few ounces in the line always tasted off. This was the biggest thing I noticed with the EVA. The beer in the EVA line after going a day without drinking tasted the same. Nothing off. So I changed both beer/gas line to EVA/Duotight.

I basically noticed this as well. The first couple ounces or whatever poured since the previous night were not sweet and lacking hop flavor after my change to EVA. I'd pick up pretty much where I left off. This got me to switch the other keg line and the CO2 line as well.

After a week or something (I've been on a trip perhaps), I do think I get some oxidation for some reason. But it takes FAR longer.