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Serving line length confusion

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gigidogg

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So, I've just filled my first two kegs with homebrew and hooked them up to CO2 in the new chest freezer conversion. Got about 7-10 days to wait on carbonation, and, honestly I want my beers to age a little more before drinking. The question I have is, I have looked up serving line length equations which tell me I need ~4 feet of 3/16 ID thickwall tubing to reduce my pressure enough to serve foam free. My pressure is set ~12PSI and my temp is ~38F. I'm shooting for 2.7 volumes of CO2. This line length seems a little low from what I've read on this board about line lengths in other folks kegerators. What are ya'll doing?
 

Evan!

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My tower came with about 4' of length, and I wasn't about to replace it without seeing how it did first.

I force-carb'd at 35psi for 2 days, offgassed twice in 3 hours, put 'em on 10psi to serve, and they were great. I've been serving this way for 3 weeks now, and I'm getting almost no foam, save for a little tiny bit from the first pour...so I'm sticking with 4' for now. I'd say see how it goes first, because I'm certainly no expert, just passing on my experience. It's best to see if what you have works before worrying about trying to fix a problem you might not even have.
 
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gigidogg

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I would not be me if I didn't make a problem before there's a problem....;)

My LHBS is about a 45 minute drive and I'd hate to cut my tubing too short and have problems the afternoon I go to pull my first draft beer at home. That would definately suck hard. Guess I'm just trying to avoid frustration. Thanks for the advice!
 

Bearcat Brewmeister

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Based on information posted on the Internet and my Fluid Mechanics textbook, I created this. It is based on the idea that beer should be set at such a pressure that it properly carbonates the beer AND pushes it against all resistance (hose diameter, gravity) such that it comes out the tap at 1 psi. It will calculate for different beer styles and serving temperatures.

I typically have a Scottish, a Porter, and an IPA on tap and they each have different line lengths and pressures:

Scottish: 3 psi, 9", 1/4" diameter line
Porter: 7 psi, 22", 3/16" diameter line
IPA: 11 psi, 40", 3/16" diameter line

As you can see, one line length does not fit all - it can significantly vary based on what style of beer you have.
 

balto charlie

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Bearcat Brewmeister said:
Based on information posted on the Internet and my Fluid Mechanics textbook, I created this. It is based on the idea that beer should be set at such a pressure that it properly carbonates the beer AND pushes it against all resistance (hose diameter, gravity) such that it comes out the tap at 1 psi. It will calculate for different beer styles and serving temperatures.

I typically have a Scottish, a Porter, and an IPA on tap and they each have different line lengths and pressures:

Scottish: 3 psi, 9", 1/4" diameter line
Porter: 7 psi, 22", 3/16" diameter line
IPA: 11 psi, 40", 3/16" diameter line

As you can see, one line length does not fit all - it can significantly vary based on what style of beer you have.
Very nicely done. The program has everything you ever wanted to know abour beer line length. My serving temps are a bit higher than those on the program but I will adjust accordingly, thanks Charlie
 

malkore

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for what its worth, 4feet sounds too short for 10psi. my LHBS sells premade picnic taps, 6feet. These let too much carbonation blow out. I replaced with 8 feet, and get perfect pours.
 

mr x

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I think you should always start with 10 feet, and cut back from there if you feel you need to. Beer line is cheap.
 

Bobby_M

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Right, it's cheap if you start with 10' but not 4, then 6, then 8, then 10!

The calculations are great in practice but for the vast majority of my beers, pale ales, IPAs, wheats, etc 10 feet is a sweet spot. The pour is a little slower, probably a 10 second pint instead of 4 but I'm not playing the "Tapper" game. What's the rush? 1.75 volume English beers would take like 15 seconds.
 

Bearcat Brewmeister

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The calculator is not based on my opinions, just on straight physics - nothing else (gravity is 9.8 m/s^2 in practice and reality;) ). With 3/16" diameter line, I have no issues at all with shorter line. Don't forget, this is also temperature dependent AND line diameter dependent. You can't accurately recommend a particular line length and pressure setting without stating the line diameter and knowing the style of beer and the height the the beer moves against gravity to the tap. What works for one person does not work for another if one of the parameters is different - there is no "one size fits all".

For example, if I chose to use 1/4" diameter line for my APA, I would need 13 feet instead of 40". Beer would not flow out line that long if it were 3/16" - 2.2 pounds of resistance per foot of line.

Charlie, the serving temps in the calculator go up to 55F in the drop down box.
 

david_42

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I have 12 feet of 3/16ths on each tap. So, some of the brews pour a little slow. BFD, none of them foam.
 

mr x

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Bearcat Brewmeister said:
For example, if I chose to use 1/4" diameter line for my APA, I would need 13 feet instead of 40". Beer would not flow out line that long if it were 3/16" - 2.2 pounds of resistance per foot of line.
This illustrates the problem with calculators. Beer is going to flow out of that 3/16" line.
 

Bobby_M

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I've run the calculators and it says I should have 5.5 feet given my temps and pressure. I've verified my gauges, they're reading correct. I get foam at 5.5 feet. I put 10 feet on and it's perfect for me. I can recommend that someone asking what size they should get would be best to start with a long line and reduce it if necessary given that it's easier to cut back later rather than buy new line and replace it. How many other people did the calculations and got foam anyway? How many poeple put 10 feet on and just left it that way because it's a slow, but foam free pour?
 

Bearcat Brewmeister

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Diameter is real important here. I have bought what was advertised as 3/16" diameter line, used the length calculated from fluid mechanics formulas, and my beer foamed. I measured the diameter of this supposed 3/16" diameter line and find that it was larger than that (yet under 1/4" - possibly metric?). The difference in resistance and therefore the length needed is about 4x between 3/16" and 1/4" diameter, so like I said, it is important to always list diameter when giving length and make sure the diameter is true.

Also, the other foaming issue comes from carbonating the beer at a higher pressure then bringing it down to serve. It will undoubtedly foam in short lengths of 3/16" like my line. I used to do a quick force carbonatation (25 to 30 psi for a day). Now I use a carbonation stone and never set the keg above its serving pressure at any time. I think this helps me out quite a bit, because I never get foam on 3/16" lines that are under 2 feet long and get 6 second pours on pints at 7 psi.
 
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