Kegerator Line length

[deadfall]

I'm starting to layout my kegerator. I have 3/16 beer line and I'm planning on 12-15 foot runs. I'm planning on two regular taps and two nitro taps. Is there any reason to go longer due to the size of the tubing? Thanks in advance.

 

[LuiInIdaho]

The things that will determine the resistance in the tube are the following:
Material that the tubing itself is made out of
The diameter of the tubing
The length of the tubing.

My comment will be with respect to tubing diameter. You are using 3/16 tubing -- which is on the smaller size (compared to 1/4 or 5/16). So I would guess that you will get more resistance from 3/16 than from 1/4. Having said that, I would think that you will be in the right range for your length. I have 3/16 tubing and I am going to try for 10 ft lengths.

I hope that this helps.

Mark

 

[slarkin712]

I have read that people have line lengths that you are considering, so perhaps it will work. I have to keg setups and neither of them have beer line this long. When serving at ~2.4-2.5 vols CO2 at a temp of ~38F I use 6-8 feet of beer line and have no issues with foaming and my pours are not too fast or too slow. With 15 feet lines at the temp and pressure I described you may have slow pours due to the resistance.
I also have a setup that serves highly carbed beers of 2.8-3.0 vols CO2 at a temp of ~38F. I use 10-12 feet lines and get a tad bit of excessive foam, but these are highly carbed beers, so it works for the style. With 15 feet lines at that temp and pressure I think you would have good pours.
You're going to have to tune your system in, so I think starting with long lines and cutting them down could work well.

 

[deadfall]

The things that will determine the resistance in the tube are the following:
Material that the tubing itself is made out of
The diameter of the tubing
The length of the tubing.

My comment will be with respect to tubing diameter. You are using 3/16 tubing -- which is on the smaller size (compared to 1/4 or 5/16). So I would guess that you will get more resistance from 3/16 than from 1/4. Having said that, I would think that you will be in the right range for your length. I have 3/16 tubing and I am going to try for 10 ft lengths.

I hope that this helps.

Mark

True, I'm using the beverage tubing that Birdman Sells. I would think it's designed to have less resistance. Thanks

 

[deadfall]

I have read that people have line lengths that you are considering, so perhaps it will work. I have to keg setups and neither of them have beer line this long. When serving at ~2.4-2.5 vols CO2 at a temp of ~38F I use 6-8 feet of beer line and have no issues with foaming and my pours are not too fast or too slow. With 15 feet lines at the temp and pressure I described you may have slow pours due to the resistance.
I also have a setup that serves highly carbed beers of 2.8-3.0 vols CO2 at a temp of ~38F. I use 10-12 feet lines and get a tad bit of excessive foam, but these are highly carbed beers, so it works for the style. With 15 feet lines at that temp and pressure I think you would have good pours.
You're going to have to tune your system in, so I think starting with long lines and cutting them down could work well.

I actually haven't given any thought to temperature or serving volumes. When carbing bottles I usually am happy with 2.1vols. I not sure what I'd be happy with when it comes to kegging. I guess I have some more research to do before I cut any lines. So if I understand you guys right 20 foot lines would cause more resistance and slower pours but less foam. Oh I see at some point the length of the tubing will be fast enough and not too foamy. The balancing point. Makes sense now. Thanks.

 

[forstmeister]

This is from the latest Beersmith newsletter:

Line Resistance is Not Futile

So how does one design a draft beer system to maintain proper balance at the tap? The pressure drop depends on resistance in the beer line. Beer lines have two types of resistance - one due to elevation change (i.e. the keg being higher or lower than the tap), and a second due to the beer lines themselves which generate friction as the beer flows through the lines.

Lets look at resistance first to keep things simple. Here are some sample resistance ratings for various popular beer lines:

3/16" ID vinyl tubing = 3 psi/ft
1/4" ID vinyl tubing = 0.85 psi/ft
3/16" ID Polyethylene tubing = 2.2 psi/ft
1/4" ID Polyethylene tubing = 0.5 psi/ft
3/8" OD Stainless tubing = 0.2 psi/ft
5/16" OD Stainless tubing = 0.5 psi/ft
1/4" OD Stainless tubing = 2 psi/ft
Generally plastic tube of smaller than 3/16" ID is not recommended - it provides too much resistance for practical use!

So now that we have the resistance factors how to we go about designing a keg system that is in balance? For the purpose of our example lets assume that you have pressurized your kegging system at a nominal 12 psi, which at a 40F refrigerator temperature represents a mid range carbonation level of about 2.5 volumes of CO2 - typical for an average American or European beer.

At the tap end of our balanced keg system we want a slight positive pressure to push the beer out, but not enough to foam. Generally this would be between less than 1 psi. So let's target a tap end pressure of 1 psi. The math from here is pretty easy to calculate the balanced line length (L):

L = (keg_pressure - 1 psi) / Resistance
So starting with our example of 12 psi keg pressure, and some typical 3/16" vinyl keg tubing (which loses 3 lb/ft) we get L= (12-1)/3 which is 3.66 feet. So a 12 psi kegging system would provide 1 psi of pressure at the tap with 3.66 feet of tubing.

 

[beaksnbeer]

Your Nitro line sets do not need to be long as the restrictor plate takes care of the 30-35psi for a 70/30 N2/CO2 (beergas blend).

 

[MonsterBrew]

This is from the latest Beersmith newsletter:

Line Resistance is Not Futile

So how does one design a draft beer system to maintain proper balance at the tap? The pressure drop depends on resistance in the beer line. Beer lines have two types of resistance - one due to elevation change (i.e. the keg being higher or lower than the tap), and a second due to the beer lines themselves which generate friction as the beer flows through the lines.

Lets look at resistance first to keep things simple. Here are some sample resistance ratings for various popular beer lines:

3/16" ID vinyl tubing = 3 psi/ft
1/4" ID vinyl tubing = 0.85 psi/ft
3/16" ID Polyethylene tubing = 2.2 psi/ft
1/4" ID Polyethylene tubing = 0.5 psi/ft
3/8" OD Stainless tubing = 0.2 psi/ft
5/16" OD Stainless tubing = 0.5 psi/ft
1/4" OD Stainless tubing = 2 psi/ft
Generally plastic tube of smaller than 3/16" ID is not recommended - it provides too much resistance for practical use!

So now that we have the resistance factors how to we go about designing a keg system that is in balance? For the purpose of our example lets assume that you have pressurized your kegging system at a nominal 12 psi, which at a 40F refrigerator temperature represents a mid range carbonation level of about 2.5 volumes of CO2 - typical for an average American or European beer.

At the tap end of our balanced keg system we want a slight positive pressure to push the beer out, but not enough to foam. Generally this would be between less than 1 psi. So let's target a tap end pressure of 1 psi. The math from here is pretty easy to calculate the balanced line length (L):

L = (keg_pressure - 1 psi) / Resistance
So starting with our example of 12 psi keg pressure, and some typical 3/16" vinyl keg tubing (which loses 3 lb/ft) we get L= (12-1)/3 which is 3.66 feet. So a 12 psi kegging system would provide 1 psi of pressure at the tap with 3.66 feet of tubing.

Follow Forstmeister's note here. Those resistance value for the tubing diameter will help you get really close to what you need, then you can dial in from there. Don't forget, when balancing a tap line at that resolution, everything comes into play... temperature of the beer, temperature of faucet, temperature of the glass, angle of pour, how quick you open the tap.... etc.

 

[day_trippr]

That Beersmith advice is based on the same misuse of tubing resistance specs that virtually every line length table, chart and calculator has made. They take a figure that is derived at maximum rate of flow (high pressure/high volume) and use that to derive line lengths, as if dispensing systems operate in that manner.

They don't.
And that's why you'll end up with too-short lines if you follow along.
It is the inspiration for probably a quarter of the threads in this forum (dubious "burst carbing" advise leading to "my beer is overcarbed" being the hands-down most prolific topics, of course )

Use this spreadsheet - download it then launch it and the cells will be unprotected. It is the only line length calculator worth using, imo...

Cheers!

 

[fosaisu]

True, I'm using the beverage tubing that Birdman Sells. I would think it's designed to have less resistance. Thanks

Which one? Birdman's got both AccuFlex Bev-Seal (the very low-resistance stuff) and generic Beer Tubing. I've only ever used the Bev-Seal and started with 18' lines for ~ 2.5 volume beers (having read up on this product, that was toward the high end of lengths recommended and I figured I could always trim it if too slow). That's been perfect for my setup (upright kegerator, ~ 8 inch rise from keg to tap, serving temp 38 degrees F) and I was never tempted to further shorten it. If you're interested in reading about others' experiences, just search the forums for Accuflex and you'll find a number of threads. [EDIT: try the threads here and here].

If you're using the generic "Beer Tubing" you'll likely want much shorter lines since the resistance will be higher. Since I've never tried this stuff I'll refrain from guessing about the proper line length.

 

[day_trippr]

^ Exhibit A.

18' of 3/16" ID tubing (and you can believe that the Bev-Seal Ultra Series 235 tubing is slick stuff inside). Meanwhile, Beersmith et al would have you believe you could get away with 6 feet...

Cheers!

 

[deadfall]

Wow thanks for all the great info. I bought the accuflex bev-seal tubing. I mostly got it because I kept reading about people tasting the vinyl tubing in their beer. I'm kind of glad I got it now. I have to get further along on my build so I can figure out the all the variables. Truthfully I still have to build the hinges for the fridge. My donated refrigerator didn't come with any. I should have them built later today. Then I'll be able to start planning the layout.

I really appreciate all the great information and the help. I can see it would be pretty easy to make a mistake and end up with foamy beer.

 

[JuanMoore]

This is from the latest Beersmith newsletter:

Line Resistance is Not Futile

So how does one design a draft beer system to maintain proper balance at the tap? The pressure drop depends on resistance in the beer line. Beer lines have two types of resistance - one due to elevation change (i.e. the keg being higher or lower than the tap), and a second due to the beer lines themselves which generate friction as the beer flows through the lines.

Lets look at resistance first to keep things simple. Here are some sample resistance ratings for various popular beer lines:

3/16" ID vinyl tubing = 3 psi/ft
1/4" ID vinyl tubing = 0.85 psi/ft
3/16" ID Polyethylene tubing = 2.2 psi/ft
1/4" ID Polyethylene tubing = 0.5 psi/ft
3/8" OD Stainless tubing = 0.2 psi/ft
5/16" OD Stainless tubing = 0.5 psi/ft
1/4" OD Stainless tubing = 2 psi/ft
Generally plastic tube of smaller than 3/16" ID is not recommended - it provides too much resistance for practical use!

So now that we have the resistance factors how to we go about designing a keg system that is in balance? For the purpose of our example lets assume that you have pressurized your kegging system at a nominal 12 psi, which at a 40F refrigerator temperature represents a mid range carbonation level of about 2.5 volumes of CO2 - typical for an average American or European beer.

At the tap end of our balanced keg system we want a slight positive pressure to push the beer out, but not enough to foam. Generally this would be between less than 1 psi. So let's target a tap end pressure of 1 psi. The math from here is pretty easy to calculate the balanced line length (L):

L = (keg_pressure - 1 psi) / Resistance
So starting with our example of 12 psi keg pressure, and some typical 3/16" vinyl keg tubing (which loses 3 lb/ft) we get L= (12-1)/3 which is 3.66 feet. So a 12 psi kegging system would provide 1 psi of pressure at the tap with 3.66 feet of tubing.

I hate articles like that, they are so misleading. Those resistance figures make it seem like line resistance is a fixed number for a given line, but it's not. It's dependent on flow rate, and those charts all assume a flow rate of 128oz/min, which is way too fast for many situations. It works ok in commercial systems where the beer is always kept at or under 36° and the carb level under 2.7vol. The warmer the beer is, or the more highly carbonated, the slower the pour needs to be to prevent the CO2 from coming out of solution and causing foaming. As soon as the flow rate is slowed down slightly, the line resistance decreases dramatically, which is why most people who serve at only 4° higher (40°) often find that they need their lines to be triple or more the length recommended by articles like the one above.

Not only that, but many of those articles and calculators suggest that there is an "ideal" line length that will create "balanced" pours. The only disadvantage to extra long lines is a slightly slower pour. And I do mean slight. Since resistance reduces with flow rate, even doubling the line length usually doesn't slow the pint fill time significantly. The advantage to longer lines is the ability to serve beers with a wide variety of carb levels at a wide range of temps without issue.

Use this spreadsheet - download it then launch it and the cells will be unprotected. It is the only line length calculator worth using, imo...

Cheers!

This. And set your pint fill time to at least 8 seconds, longer if your serving temp is higher. For 40° I'd suggest at least a 10 second pint fill.

 

[deadfall]

I poured my first pint last night. I ended up with 18 foot serving lines. The kegs had only been on 12psi co2 for 1 week. I had a friend over and it seem like a good time to see how it's coming along. 7 beers and it was really nice. I'm kind of glad its only a 5% beer. Almost a perfect pour. Although I had expectations of glasses of only foam. So being a little under carbonated was a lot better then foam. Kind of unreal, no bottles to wash. I'd say in three weeks and it's going to be perfect. Thanks for all the help.