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I've been using a converted chest freezer for nearly a year now for storing and dispensing from corny kegs and for lagering. Depending on whether I have kegs of homebrew, I may have a sanke keg of commercial brew.

I just added two pieces of equipment to the system: a one-to-three gas manifold and a second sanke tap and hooked up two sixth barrel kegs from the same brewery. There was a large discrepancy in how the two kegs dispensed -- one was slow, as if there was almost no pressure; the other was way too pressurized and foamy.

When I adjust gas settings at all -- change pressure on the regulator, bleed gas with pressure relief valve, etc. -- the system hums like a harmonica. This may have come from one of the pressure relief valves (on the sanke tap or on the manifold) and seemed to be a red flag. I have not been able to detect any leaks. Upon visual inspection, everything seems fine as well.

My question is this: Why would these two identical kegs fitted with identical taps filled with beer from the same brewery dispense so dramatically differently? Does one tap have a defective pressure relief valve?

Secondly, a big BBQ party drained both kegs in a day, so I didn't have much time to troubleshoot. How can I further test this if both kegs are blown?

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My 1-4 manifold does the same harmonica thing any time I run gas through it. I think it's just the check valves and doesn't seem to be an issue. –  JoeFish Aug 14 '12 at 19:34
    
Thanks, JoeFish. Have you ever been able to find any leaks with your manifold? –  Jordan Aug 16 '12 at 0:13
    
No I have not.   –  JoeFish Aug 16 '12 at 11:01
    
Does the adjustment of the regulator temporarily correct the unequal flow? I'm not sure how that relates to the problem of unequal dispensing as the question is worded. Could that part be deleted and not change the issue? –  bmike Aug 27 '12 at 19:26
    
Good point, bmike. Perhaps I should instead split this into two questions. The two issues are the humming/harmonica-type sound when any gas settings are adjusted, and the dramatically uneven flow. Although I can't confirm the issues are related, I put both into one question as both issues appeared at the same time. –  Jordan Aug 28 '12 at 20:11

1 Answer 1

up vote 1 down vote accepted

Humming is normal, dont worry about that. Nearly everything hums on my 6 tap sanke system. Its just how the gas get squeezed through manifolds, valve, and seals.

On to the second question. There are a few things that could cause this. I am going to assume the kegs are 2 different styles of beer from the same brewery, not just 2 kegs of the same beer.

I have noticed that a full body beer and/or a high ABV beer I need to carbonate at a higher than the desired 2.8 volumes to achieve the same perceived carbonation. So this type of beer may seem either flat or super carbonated depending on how it was carbonated. Also the temperature the brewery carbonated the beer at. However this is just something I wanted to throw out. I dont think this is the problem, though it could be.

At the same time you need resistance in your beer lines in order to keep the CO2 in solution. This is achieved by tubing diameter and the length of the beer line. Beer lines that are not insulated will also affect the CO2 in the beer. A warmer line would cause more CO2 to come out of suspension and force the beer out quicker and you end up with a pint of head.

The beer line resistance can be calculated below.

Refer to this link for the full formula: http://www.brewersfriend.com/2009/07/18/getting-a-good-pour-kegged-beer-co2-line-length-and-pressure/

But for a quick look:

L = (P -(H x .5) – 1 ) / R

Where: L = length of beer line in feet P = pressure set of regulator H = total height from center of keg to faucet in feet R = resistance of the line from the following table 1 = residual pressure remaining at faucet (this can be increased to 2 if you need to increase pressure to increase dispense rate)

Line Type: Resistance: 3/8” OD stainless beverage tubing .2 5/16” OD stainless beverage tubing .5 1/4” OD stainless beverage tubing 2 3/8” ID plastic beer line .11 5/16” ID plastic beer line .17 1/4” ID plastic beer line .7 3/16” ID plastic beer line 2.7

So, depending on your line diameter, length of tube, and the beer's carbonation volume. You could end up with a gusher or a trickle.

One final thought. I have had kegs of Guinness that just trickle out. Even at >50 PSI. We are all human and sometimes the beer just doesn't carb like we thought.

Hope this helps!

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Pardon the slow reply, Grico. It took a while to be able to test this same scenario. 1. Thanks for setting my mind at ease with the humming. 2. The forumla was particularly helpful, and I think the system is adequately configured now. There was also a defective gasket that blocked flow somewhat (it's silicon, and sort of a backflow preventer, I believe) in one of the Sanke taps. All things considered, the system is working correctly now. –  Jordan Jan 11 '13 at 2:43

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