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 Home Brew Forums > Optimal beer line length? What is it?
08-13-2010, 09:34 PM   #1
ipatch
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 Optimal beer line length? What is it?

I acquired my kegerator second hand, and was wondering what the optimal keg line length is. Here is a picture of the current line length, and for some reason this length just seems a little counter productive, but I have been known to be wrong.

The length of the line is approximately 8ft from the top of the inside fridge to the ball lock disconnect.

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08-13-2010, 10:28 PM   #2
CodyRay
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That was probably done to provide for the correct resistance. The head pressure, carbonation level and type of tap determine how long that line should be. 10psi of head pressure means the line needs to impose 10psi of resistance. Find out what kind of line that is, how far the beer needs to vertically travel from keg to tap, and the type of tap that will be used. Each of these will impose restriction. A foot of vertical travel imposes .5psi of restriction.

So say you want to run 15psi of head pressure. To keep things simple lets say you are running a cobra tap which has almost no restriction. The vertical travel will be roughly zero because you can hold the tap at the hight of the keg fittings. The line is 3/16th inch vinyl which has 3psi restriction per foot. Because the system has a cobra tap, no extra pressure is needed to get the beer to run, however an externally mounted tap would require the psi raised a couple pounds for it to run right. 15 divided by 3 is 5, so you would need 5 feet of beer line to get the beer to flow correctly.

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08-14-2010, 12:09 AM   #3
Bobby_M
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There's no way in hell he'll get a decent pour at 15psi with 5 feet of line. I think 3psi drop per foot is a high estimate, it's probably closer to 2.

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08-14-2010, 02:53 AM   #4
dogtailale
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Quote:
 Originally Posted by CodyRay That was probably done to provide for the correct resistance. The head pressure, carbonation level and type of tap determine how long that line should be. 10psi of head pressure means the line needs to impose 10psi of resistance. Find out what kind of line that is, how far the beer needs to vertically travel from keg to tap, and the type of tap that will be used. Each of these will impose restriction. A foot of vertical travel imposes .5psi of restriction. So say you want to run 15psi of head pressure. To keep things simple lets say you are running a cobra tap which has almost no restriction. The vertical travel will be roughly zero because you can hold the tap at the hight of the keg fittings. The line is 3/16th inch vinyl which has 3psi restriction per foot. Because the system has a cobra tap, no extra pressure is needed to get the beer to run, however an externally mounted tap would require the psi raised a couple pounds for it to run right. 15 divided by 3 is 5, so you would need 5 feet of beer line to get the beer to flow correctly.
Im running 3/16th x 6 feet of line 15psi. REAL SLOW

I can turn on the tap (picnic) today and get a beer tomorrow.

Im guessing 3ft for me would be better. Just a guess
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08-14-2010, 06:09 AM   #5
CodyRay
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Quote:
 Originally Posted by Bobby_M There's no way in hell he'll get a decent pour at 15psi with 5 feet of line. I think 3psi drop per foot is a high estimate, it's probably closer to 2.
I'm telling you what I read from Dave Miller's book.
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08-16-2010, 04:34 PM   #6
ipatch
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Currently I have a keg of Killians in there. It is a 1/6 barrel, and I have not altered the line length. I set my CO2 pressure around 4PSI, so I can save on CO2 because I only have a 5lb tank, and also to keep the foam/head of the beer to a minimum, and so I can get a complete glass of beer. The beer is not gushing out of the tap, but it fills the glass with little head/foam.

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08-17-2010, 12:06 AM   #7
RichBenn
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Quote:
 Originally Posted by ipatch Currently I have a keg of Killians in there. It is a 1/6 barrel, and I have not altered the line length. I set my CO2 pressure around 4PSI, so I can save on CO2 because I only have a 5lb tank, and also to keep the foam/head of the beer to a minimum, and so I can get a complete glass of beer. The beer is not gushing out of the tap, but it fills the glass with little head/foam.
You need to read up on carb charts. Unless you are drinking all in a day, the proper thing is to set the PSI based upon desired carbonation for a given temperature. Then you adjust line length for that PSI to avoid foaming.

At 4 PSI, there is NO temp that won't freeze the beer that'll maintain proper carbonation on 95% of beer styles. On a properly "already carbed" commercial beer, you can, initially, get a good pour with that pressure. But the beer will lose it's carbonation over time. Keeping the pressure proper will ensure equilibrium and mantain the carbonation. Unless you have leaks, you will not "waste" CO2.

BobbyM, IMHO, has some excellent posts about line length. Read up on carbonation charts, then read Bobby's posts on carbing and line length. You'll be an expert in no time.
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08-17-2010, 01:39 AM   #8
ipatch
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Quote:
 Originally Posted by RichBenn You need to read up on carb charts. Unless you are drinking all in a day, the proper thing is to set the PSI based upon desired carbonation for a given temperature. Then you adjust line length for that PSI to avoid foaming. At 4 PSI, there is NO temp that won't freeze the beer that'll maintain proper carbonation on 95% of beer styles. On a properly "already carbed" commercial beer, you can, initially, get a good pour with that pressure. But the beer will lose it's carbonation over time. Keeping the pressure proper will ensure equilibrium and mantain the carbonation. Unless you have leaks, you will not "waste" CO2. BobbyM, IMHO, has some excellent posts about line length. Read up on carbonation charts, then read Bobby's posts on carbing and line length. You'll be an expert in no time.
good stuff, I will try and do a bit more research in my spare time
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