balancing keg system with different size lines

So I need to figure out line length for my kegging setup, the thing is that right now I have some 3/16 ID line and some 1/4 ID line, but not enough of either to use the same size line on both kegs. This is the setup:

faucets 2 feet above the center of the kegs. The fridge is a solid 38 degrees, and I'm aiming for about 2.2-2.4 volumes of Co2. I checked out http://hbd.org/clubs/franklin/public_html/docs/balance.html and this says I should have a pressure of about 8-9 psi, then the lines measure out to be around 2.25 ft of 3/16 and 9 something ft of 1/4. This difference is astounding, plus I feel like the psi it reccomends is a bit low. It seems everyone here always talks about having their regulators set between 13-15 psi. Should I just go buy more line of one or the other type? I think I need to buy more 1/4 ID line anyway.

Just double checking. You know what they say, "measure twice, cut once...."

ranch

I pour hefeweizen, keg is at 23psi - using 3/16 line I needed about 7.5 feet. If you are using lower keg pressure then it might be easier to use the 1/4 line, just to allow distance from tap to keg. If you think you might do a lot of hefes, go with the 3/16 just so you won't be coiling 17 (or whatever) feet of 1/4" tubing.

Unless your keg fridge is remote, meaning more than 10' from the taps, you don't want to use 1/4" ID tubing. 3/16" ID thick walled beverage tubing is what you should use.

I serve through 10' of tubing regardless of the style being served. The only thing that changes with the serving pressure is the pour rate. A Hefe served at 18 psi has a pour rate that is faster than a stout served at 8 psi. Both will serve foam free though, that is the goal!

It really is a game of compromise. Choose a length of line that gives you the flexibility to serve higher carbed beers and the trade off will be that when you serve lower carbed beers your pour rate will be a little slower. I have not found this to be a problem.

There is a rule of thumb that each foot of 3/16" ID beverage line has a pressure drop of 2 psi. That is a little simplistic. There is a large set of variables involved in balancing your system. The higher the carbonation level - the slower you want the pour. The faster the pour the quicker the co² will be knocked out of solution during the pour.

The rule of thumb that I use is:


Carb level = Desired Pour rate = Effective 3/16" Line Resistance at that given volume of CO2

1.8 to 2.3 volumes = 110-120 oz/min = 2.19 lbs/ft
2.4 to 2.6 volumes = 100-115 oz/min = 1.81 lbs/ft
2.6 to 2.8 volumes = 90-105 oz/min = 1.40 lbs/ft
2.8 to 3.0 volumes = 75-85 oz/min = 0.94 lbs/ft

So you can see that just using the 2 psi per foot pressure drop figure for 3/16" ID beverage tubing to balance your system does not take all factors into consideration.

I have a kegerator with a 5' line with a flare fitting to attach a ball-lock QD on the end. Can you get a connector that mates with the flare fitting to attach a line extension if serving at higher PSI? I've never seen such a beast for sale on any homebrew sites.

Buford said:

I have a kegerator with a 5' line with a flare fitting to attach a ball-lock QD on the end. Can you get a connector that mates with the flare fitting to attach a line extension if serving at higher PSI? I've never seen such a beast for sale on any homebrew sites.

Click to expand...

It has been tried but it does not work. The addition of fittings in the line that would allow for a convenient change in line length add a point of restriction and pressure drop and will create more foam, not eliminate it.

That is why I stated that it is a game of compromise. Choose a line length that will balance out the highest carb'd beer that you anticipate serving. Then any lower carb'd beers that you serve through that line will pour a little slower but will be foam free.

This is all very helpful. But when I measure my lines, do I want to drop all of my pressure by the time the beer hits the faucet? I don't imagine this would be right, so how much pressure should I aim to have at the end of the line? 1 psi? 2 psi?

and please help me to make sure I understand this: assuming I want to go for the 2.4-2.6, my fridge is 38 degrees, so I want to use about 11.2 psi (by that website I posted previously). So, lets say I'm aiming for 1 psi at the faucet:

11.2-1=10.2
10.2 psi / 1.81 (psi/ft) = 5.64 ft. of 3/16 ID line.

Is that the right math? What should I assume for the height of the faucet above the keg, or is that negligible?

Cheers.

ranch

It's a lot easier and cheaper in the long run to add an extra 2 feet per tap and try it out. If you get a really slow pour, but good overall carbonation, trim a foot off and try again.

You will never drop the pressure completely, not even if you have 100' of tubing. You will still get flow out of the end, albeit very slowly. As Bobby stated, go a little long on the serving line length and if your pour is foam free, but the pour rate is too slow, cut off some until your pour rate is satisfactory. I like to be able to pour a pint in about 10 seconds.

ranch said:

This is all very helpful. But when I measure my lines, do I want to drop all of my pressure by the time the beer hits the faucet? I don't imagine this would be right, so how much pressure should I aim to have at the end of the line? 1 psi? 2 psi?

and please help me to make sure I understand this: assuming I want to go for the 2.4-2.6, my fridge is 38 degrees, so I want to use about 11.2 psi (by that website I posted previously). So, lets say I'm aiming for 1 psi at the faucet:

11.2-1=10.2
10.2 psi / 1.81 (psi/ft) = 5.64 ft. of 3/16 ID line.

Is that the right math? What should I assume for the height of the faucet above the keg, or is that negligible?

Cheers.

ranch

Click to expand...

I'm ready to cut line for my Sanyo, and I've done my balancing math, and am double checking my math vs. others experiences.

First of all, the math in this post is not equal to the equation shown on the link. I know, probably too late now for Ranch to use, but when someone else does a search...

"Calculating length of beer line

Once you have established the CO2 pressure on your keg, you can determine what length of beer line you need to balance the system. The basic premise is that we need to drop nearly all the pressure between the keg and the faucet, leaving 1 psi to actually get the beer to come out. The formula for calculating the line length is:

L = P - (H * .5) - 1
R

where

* L = length of beer line in feet
* P = pressure set on regulator gauge
* H = Total height from the center of the keg to faucet in feet
* R = Resistance of line from the following Resistance Table
* 1 = this is the residual pressure remaining at the faucet *

* If you need a higher dispensing pressure to increase the dispense rate, use 2 instead of 1.

This formula determines what line size & length to use to drop all but 1 psi of pressure, leaving just enough to dispense the beer."

By the numbers given for the height above keg, carb level CO2 volume vs. serving temperature, and 2.7 for 3/16" line loss per foot of hose, I get this:

L = P - (H * .5) - 1
_____________ =
R


11.2 - (2 x .5) - 1
______________ =
2.7


11.2- 1- 1
_________ =
2.7


3.4' or 3' 4.8" of 3/16" line.

NOT 5.64 of 3/16" line.


NOW, .... what gets me is what to serve an IPA at for Carb Volume,

Carbonation Guide

"Beer style Volumes CO2 Beer style Volumes CO2
British-style ales 1.5 - 2.0 Porter, Stout 1.7 - 2.3
Belgian ales 1.9 - 2.4 European lagers 2.2 - 2.7
American ales & lagers 2.2 - 2.7 Lambic 2.4 - 2.8
Fruit lambic 3.0 - 4.5 German wheat beer 3.3 - 4.5"

Like, 2.0..........? ???

Really. Are we still talking about pouring beer here?