Length of beer lines

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TexasGuy

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I’ve done my first keg. If I store my beer at 34 degrees, and are using a soda keg with with a standard size kegorator, do I really need 10-20 feet of beer line if I prefer higher carbonated beer? I’m using 1/4” beer line to match the barbs in the QDs. I’m getting a fairly foamy beer when pushed at 5 psi

Thanks for your feedback.
 
If you took a poll I bet 90+% of folks are using 3/16" ID beer line over 1/4" barbs.

Some of the rest are using 1/4" ID lines because they have to go a long ways from keg to faucet, others are actually using even thinner ID lines (like 4mm) and commensurately short lines because they can.

Anyway, if you want to find the optimal line length for a given CO2 pressure there truly is only one beer line length calculator worth using and you'll find it here. Plug in your particulars and it'll spit out a line length. It works really well for vinyl lines, not so much for PET lined beer lines or the new EVAbarrier tubing I'm now using. A reasonable adjustment factor for those is to add +50% of the calculated length.

Beyond pure line ID, length and type, there can be other causes for foam. If you carbonate a beer to a high level (say above 2.4 volumes which is pretty close to the average for most ales) but dispense the beer at a pressure significantly lower the dispensing pressure can't hold all of the dissolved CO2 in solution and you'll get "CO2 breakout". And bubbles beget bubbles - what might seem to be a minor imbalance can easily turn into a CO2 cascade that leaves an inch of beer below five inches of foam.

Bottom line, reference our favorite carbonation table, find your beer temperature on the Y-axis, scan across that row to the level of carbonation you desire (expressed in "volumes of CO2" where, again, 2.4 is about average) then run up that column to find the pressure that will maintain that carbonation level. Then use that pressure with Mike's calculator to find the optimal line length - or just use 1 foot of 3/16" ID beer line per PSI.

In the scheme of things, 5 psi is pretty low for most beer styles...

Cheers!
 
TexasGuy said:
I’ve done my first keg. If I store my beer at 34 degrees, and are using a soda keg with with a standard size kegorator, do I really need 10-20 feet of beer line if I prefer higher carbonated beer? I’m using 1/4” beer line to match the barbs in the QDs. I’m getting a fairly foamy beer when pushed at 5 psi

Thanks for your feedback.
Click to expand...
To force carbonate and also serve beer at 10-12 psi I use eleven-foot lengths of 3/16 ID beer line. This combination gives foam free pours with my kegerator and with picnic taps.
 
Use 3/16 beer line on 1/4" barbs. Plug the geometry into a line length calculator, then add 4-6 feet. Try it. If its pouring too slow cut a foot off the line and try again. FWIW using flow control taps helps give you the ability to adjust pressure without changing line length. FYI my lines are 15 feet long
 
I run 4mm EVA Barrier lines onto 1/4" barbs on my Flow Control Ball Lock QD (it's a tough fit, but they will with work). 3 foot lines with 12 PSI @ 40 degrees, and it's a slow pour. Slow enough I may shorten to 2.5 feet.
Let me say that again:
3 feet at 12 PSI.
Boom.
 
@TexasGuy , the order of how to do it is what finally hit me as most important, per @day_trippr ; find the PSI given the temp. ONLY THEN calc the line length now that temp and psi are set. Change anything, and you risk imbalance.
 
I didn't mention it earlier but my serving kegs are refrigerated at 36F(2.2C) and use 1/4"(6.35 mm) barbs. I ordered the 5 mm ID x 8 mm OD EVABarrier double wall tubing a while ago but haven't replaced the existing beer lines with it yet. The EVABarrier tubing size is close to the 3/16" ID lines I use now so I'll cut them to the same eleven-foot lengths as the old beer lines.
 
If you ordered the 5mm ID EvaBarrier tubing note 5mm is actually a slightly wider bore than 3/16". I would add a couple of feet as insurance remembering it can be cut back once you've had time to judge the pours...

Cheers!
 
I ran the calculator suggested by @day_trippr for my setup and got a line length of just over 10ft. I’ve noticed that my first pint has considerably less carbonation than subsequent pints for that drinking session.

My question, somewhat related to this thread, does the beer in the line lose carbonation? If so, can someone explain this. To me, the entire environment is a closed system and should therefore contain the same pressure throughout. This, however, doesn’t seem to be the case.
 
Kickass said:
I ran the calculator suggested by @day_trippr for my setup and got a line length of just over 10ft. I’ve noticed that my first pint has considerably less carbonation than subsequent pints for that drinking session.

My question, somewhat related to this thread, does the beer in the line lose carbonation? If so, can someone explain this. To me, the entire environment is a closed system and should therefore contain the same pressure throughout. This, however, doesn’t seem to be the case.
Click to expand...

What kind of beer line are you using? If it's the standard vinyl line, then it's letting oxygen get through so the first few ounces are oxidized. That's what I was referring to above when the Eva Barrier line, which doesn't let oxygen pass through.

When I used vinyl lines, I would have to either throw out the first couple ounces of the day, or chug the flat beer, before pouring a normal pint. With the new line, it's not an issue anymore.
 
Carolina_Matt said:
What kind of beer line are you using? If it's the standard vinyl line, then it's letting oxygen get through so the first few ounces are oxidized. That's what I was referring to above when the Eva Barrier line, which doesn't let oxygen pass through.

When I used vinyl lines, I would have to either throw out the first couple ounces of the day, or chug the flat beer, before pouring a normal pint. With the new line, it's not an issue anymore.
Click to expand...

Interesting. They are vinyl.

I’m still trying to make sense of this. How does oxygen, under normal atmospheric pressure, penetrate a vinyl line that’s sitting at 12psi. Pressure equalizes from a high source (keg line) to low (atmosphere).
 
day_trippr said:
If you ordered the 5mm ID EvaBarrier tubing note 5mm is actually a slightly wider bore than 3/16". I would add a couple of feet as insurance remembering it can be cut back once you've had time to judge the pours...

Cheers!
Click to expand...
Although I ordered 39 feet of tubing I don't think a 64th of an inch in diameter will make a difference in eleven foot runs.

"The 5 mm (13/64") ID size is perfect for draft applications where a longer beverage line is needed. We recommend using 10-12 ft. per line for adequate flow resistance."
 
Kickass said:
Interesting. They are vinyl.

I’m still trying to make sense of this. How does oxygen, under normal atmospheric pressure, penetrate a vinyl line that’s sitting at 12psi. Pressure equalizes from a high source (keg line) to low (atmosphere).
Click to expand...
While that is the intuitive thought, that's not how gases actually work.
If the barrier (vinyl, in this case) is gas-permeable, Oxygen will permeate it and internal gas (CO2) will diffuse out of it regardless of pressure differential from atmosphere to inside the tube.
Gas molecules easily and readily "swim upstream".

It took me a while to make sense of this too, and initially I was resistant until it was proven to me, since it is so counter-intuitive.
 
Cavpilot2000 said:
While that is the intuitive thought, that's not how gases actually work.
If the barrier (vinyl, in this case) is gas-permeable, Oxygen will permeate it and internal gas (CO2) will diffuse out of it regardless of pressure differential from atmosphere to inside the tube.
Gas molecules easily and readily "swim upstream".

It took me a while to make sense of this too, and initially I was resistant until it was proven to me, since it is so counter-intuitive.
Click to expand...
If this is the case, logically, the next concern would be that my beer is oxidizing in the keg. Would this be an accurate assumption of a second order effect? Or is the oxidation confined to the vinyl keg line only?
 
PET bottles are gas permeable but beer will hold its carbonation in them for six months before any carbonation losses are detectable.

But PET bottles are thin compared to the 1/8” thick beer line walls. And they don’t have 12 psi of Co2 attached to them. Since Co2 and O2 are gases why wouldn’t the Co2 permeating the beer line walls under pressure keep the O2 out?
 
day_trippr said:
Read up about partial pressure gas laws.
O2 and CO2 care nothing about each other's partial pressure and will go where they want...
Cheers!
Click to expand...
I admit I haven’t read that but could you briefly explain how oxygen at atmospheric pressure and carbon dioxide under twelve pounds per square inch of pressure interact?

I would think the carbon dioxide under pressure would prevent oxygen at atmospheric pressure from penetrating the beer line.
 
By diffusion a gas will try to equalize partial pressure. As noted it doesn't care about the presence of other gases, behaves as though they don't exist; it simply wants to spread itself equally everywhere. A gas will move from a region of higher concentration of itself to one of lower concentration, as though filling a vacuum. Absolute pressure is irrelevant. CO2 wants out of the line and oxygen wants in, and as long as there is a permeable material they will exchange places. Like they say about gravity, it's the law.
 
Robert65 said:
By diffusion a gas will try to equalize partial pressure. As noted it doesn't care about the presence of other gases, behaves as though they don't exist; it simply wants to spread itself equally everywhere. A gas will move from a region of higher concentration of itself to one of lower concentration, as though filling a vacuum. Absolute pressure is irrelevant. CO2 wants out of the line and oxygen wants in, and as long as there is a permeable material they will exchange places. Like they say about gravity, it's the law.
Click to expand...
I never would have guessed that would be the case. Here’s what I don’t get. A gas under pressure in a closed tube is compressed. Compressed gas isn’t more concentrated inside the tube than the atmospheric gas outside the tube?

The other question I have is how long does it take gas to penetrate a tube wall of varying thickness?
 
ScrewyBrewer said:
PET bottles are gas permeable but beer will hold its carbonation in them for six months before any carbonation losses are detectable.

But PET bottles are thin compared to the 1/8” thick beer line walls. And they don’t have 12 psi of Co2 attached to them. Since Co2 and O2 are gases why wouldn’t the Co2 permeating the beer line walls under pressure keep the O2 out?
Click to expand...
PET is actually the least gas permeable common polymer. Silicones are by far the worst.

Brew on :mug:
 
5mm = 0.1968498", R=1/2 ID = 0.0984249, R-squared = 0.00968746094001, Pi*R-squared = 0.03043405612107348870681886135705

3/16"= 0.1875", R=1/2 ID = 0.09375, R-squared = 0.0087890625, Pi*R-squared = 0.02761165418194154213492557661086

0.03043405612107348870681886135705/0.02761165418194154213492557661086 = 1.1022177780633599999999999999998

So, 5mm ID provides a little more than 10% greater cross-sectional area than 3/16" ID. Which may or may not matter...

Cheers! (Vaya con Dios :))
 
ScrewyBrewer said:
I never would have guessed that would be the case. Here’s what I don’t get. A gas under pressure in a closed tube is compressed. Compressed gas isn’t more concentrated inside the tube than the atmospheric gas outside the tube?

The other question I have is how long does it take gas to penetrate a tube wall of varying thickness?
Click to expand...
It's relative concentration, i.e. partial pressure, not absolute pressure, that matters. O2's partial pressure is higher outside, it wants to flow across the membrane, and vice versa with CO2.

As for the second question this may help, or not. Might just make your head hurt like mine trying to do the math. I've seen it done for us on other threads. http://www.********************/brewing-methods/beer-serving-oxygen-ingress/

What I know is it happens fast enough to perceptibly stale the beer in a vinyl line in the short time between pours even in a session, and the rest of the keg soon after. Switching to a good barrier tubing was enlightening. A point that might escape many in all of this is that your gas line matters too. Pressure in your gas cylinder can remain unchanged, but if the line attached is gas permeable, the contents will be inexorably moving toward having the same composition as the outside air.
 
ScrewyBrewer said:
I’ll take your word for it but I’m confident I couldn’t tell the difference in pours anyway.
Click to expand...
@day_tripper so far I have...
3.1416*2.5*2.5=19.635 (5mm)

3.1416*2.381*2.381=17.810 (4.763mm)

Difference of 19.635 and 17.818 = (19.635 - 17.818)/((19.635 + 17.818)/2) = 1.817/18.7265 = 0.0970 = 9.702%

Thank you I stand corrected.
 
Robert65 said:
It's relative concentration, i.e. partial pressure, not absolute pressure, that matters. O2's partial pressure is higher outside, it wants to flow across the membrane, and vice versa with CO2.

As for the second question this may help, or not. Might just make your head hurt like mine trying to do the math. I've seen it done for us on other threads. http://www.********************/brewing-methods/beer-serving-oxygen-ingress/

What I know is it happens fast enough to perceptibly stale the beer in a vinyl line in the short time between pours even in a session, and the rest of the keg soon after. Switching to a good barrier tubing was enlightening. A point that might escape many in all of this is that your gas line matters too. Pressure in your gas cylinder can remain unchanged, but if the line attached is gas permeable, the contents will be inexorably moving toward having the same composition as the outside air.
Click to expand...
I'll be changing my current beer line tubing over to the EVABarrier double wall tubing this weekend. Thank you.
 
Kickass said:
If this is the case, logically, the next concern would be that my beer is oxidizing in the keg. Would this be an accurate assumption of a second order effect? Or is the oxidation confined to the vinyl keg line only?
Click to expand...

In a nutshell, yes.
The guys who are really hardcore about preventing oxidation disconnect their lines (at the QD) from the keg when not in use. That prevents the oxygen that is getting into the beer lines from diffusing into the keg.

I, despite being a Low Oxygen (aka LODO) Brewer, am not THAT hardcore except when I don't plan to use my kegs for several days. I figure I've put the best oxygen barrier tubing I can on my system and hope to use it up before it gets oxidized.

Remember, the tubing is not impermeable, but something like EVA Barrier is far less permeable than, say, old school vinyl or many of the other materials out there, so while oxygen is getting in, my hope is that it is slow enough that I can rest easy and not worry about it.
 
Re partial pressures, I read on here somewhere a really good analogy about the size of O2 and CO2 molecules and barriers and you have to think of it like marbles moving through a 3' diameter tube. There may be more CO2 coming out than O2 going in, but there's a lot of space ("so many asteroids, hardly any hit Earth") between.
 
ScrewyBrewer said:
I admit I haven’t read that but could you briefly explain how oxygen at atmospheric pressure and carbon dioxide under twelve pounds per square inch of pressure interact?

I would think the carbon dioxide under pressure would prevent oxygen at atmospheric pressure from penetrating the beer line.
Click to expand...
Imagine you have 50 guys (CO2) on one end of a football field, shooting BB guns. On the other end, you have 1 guy (O2) shooting his BB gun back at them. Gas particles are so small, with such a huge area around them, that it is very unlikely that any of those BB's are going to collide and knock each other off course. It might happen every once in a while, but most of them are going to get through.
 
how many decades has vinyl lines been the norm? I don't get why suddenly EVA lines are a must. I guess everything is permeable to some extent, be it in a few seconds to a few centuries or more. I don't think anything is truly 100% solid.
 
odie said:
how many decades has vinyl lines been the norm? I don't get why suddenly EVA lines are a must. I guess everything is permeable to some extent, be it in a few seconds to a few centuries or more. I don't think anything is truly 100% solid.
Click to expand...
Because we are starting to realize that our palates becoming so used to oxidized beer that it actually becomes the desirable norm, is not a good state of affairs!
 

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