My regular serving line is 3/16" ID. I want to build a jumper so I can transfer carbonated beer from keg to keg. I have some extra 1/4" ID line- is there a problem associated with using this diameter to move chilled carbonated beer to another tank?
Assuming you’re transferring under pressure, the line diameter won’t make a difference.
How are you planning on venting the receiving keg?
I’ll pull and twist the pressure-release valve or just put a gas-connect on. This also is what concerns me- if the pressure is vented in receiving keg then won’t the beer foam? Or do I need to vent it periodically just to keep some pressure on but not enough to keep from filling?
Totally new to me and I’d like to know in advance what to expect instead of crying to you guys about it when a problem occurs… 8)
I have always just vented it occasionally by pulling the pressure release. I say “always” when in reality I’ve done this maybe a half-dozen times.
If you’re transferring slowly and don’t blast out all the pressure, I don’t think you get too much foam.
I think if you transfer at low psi, you shouldn’t have much of a foaming problem - I never have at least.
Ideally what you’d want to do is put a spunding valve on the receiving keg and set it 2-3 psi below the head pressure on the sending keg. Barring that I think watching the flow rate through the tubing and venting the PRV for a few seconds every time it slows/stops would work.
I do this when taking kegs somewhere and want sediment free.
I also just vent the keg periodically. Not sure about where you are but here it’s humid enough that I can follow the progress by the condensation on the outside of the keg as the cold beer fills the new keg. When that looks like it’s really slowed or stopped, I vent. I do it slowly though. I also use a long clear line (10 feet or so) so that when I see sediment/gas coming from the first keg, I can pull it off before it reaches second keg.
I also fill from out to out so that the beer is filling from the bottom up and not falling into the keg through the in tube. Not sure if it matters but I’m happy with what I’m doing.
Since I’m doing it to avoid cloudy beer, I usually drink the first pint or so while it’s transferring and then avoid the dregs.
This is important. I just assumed this is what Euge is doing, but it’s a good point to bring up.
Tip 5 on this list : Five Things That Made Brewing Easier For Me | Braukaiser might be of interest. That’s how I transfer carbonated beer.
Kai
This indeed- was my intention. But a good point nonetheless. ;D
And thank you Kai for the link. I’ve figured out 1,2 & 3 over the years but did not think to weigh the yeast!
And #5 such a great idea!
Of course I knew Euge would be doing it right but I mentioned it for the next generation of brewers that are searching this forum 10 years from now just in case they didn’t think about that 
And I was at the LHBS (such great guys!) this afternoon to pick up new 3/16" ID beer line. Mine was 5.5 years old and even though I cleaned them on occasion they have become quite stained. Furthermore I feel that there is bio-film in the lines that is bringing some “house flavor” to the party. 
Better to replace- no?
Anyway, their guy advised me to use 10’ of the beer line to increase resistance to reduce foaming. Mine are less than 4’ and never had a problem with foaming unless the beer is overcarbonated for my system settings. I didn’t agree but kept that to myself…
I’ve gone with this equation: L= (P-(H*0.5)-1)/R
or (11.8-(2’*0.5)-1)/2.7=L (L=3.63’)
Now if I wanted to start serving Hefeweizens or Belgian style brews the length should be at least 7.5’!
The equation had me wondering about transfers and potential loss of precious carbonation.
Since you’re under pressure, you shouldn’t lose carbonation.
You may get foaming due to the transfer, but it should all go back into solution in the new keg.
The problem with assuming an unrealistically large pressure drop, like 2.7 psi/ft, is that it will only give good results for one particular length/pressure combination, where it balances out the fixed pressure drop due to the other hardware in the system. In order to get consistently good results you need to account for both the linear and constant pressure losses.
http://seanterrill.com/2011/11/11/a-more-accurate-approach-to-draft-system-balancing/
Thanks Sean. I’m gonna have to wrap my head around that! 