finally IDed my keggin problem - can I solve it with a check valve?

I have a side-by-side fridge modified to serve on the left and ferment on the right. The position of the taps (perlick forward-sealing) and kegs means that one of the kegs is higher than the taps and two are below the tap height. I have had foaming problems off-and-on since I setup my rig. I have experimented with different lengths of hose as well as temperatures and pressure settings.

I noticed something today - with my coil of 3/16 hose in there, there are "dead zones" in the line filled with air or foam. When I pour a beer, I think the dead zones are getting spit out in the form of foam. I am surprised that the quick disconnect doesn't act as a check valve, preventing beer from flowing backward after pouring. But sure enough, if I watch the lines after I turn off the tap, I see bubbles and air flowing backward.

So can I just add a 3/16" check valve in line right after the quick disconnect fitting? I want all the beer drawn past the pinlock fitting to stay in the line until the next pour.

 

Not an expert, but I doubt that a check valve will resolve your issue. It's not a common liquid line component and may actually make the problem worse. What you are calling "air" is CO2 either coming out of solution or being introduced into the liquid line from the keg headspace.

If the CO2 is from the headspace then it is likely a failure of the o-ring that seals the dip tube to the keg's threaded port.

CO2 coming out of solution is generally caused by inadequate flow resistance provided by the serving line and tap. Many factors come into play, including carbonation levels, line length and cross-section, temperature and height differentials, restrictions/discontinuities, etc.

Questions: How long are the beer lines? How are you carbonating? What is your serving pressure and is it different from your "carbonation pressure"?

 

I thinking the keg on the top is much warmer than the bottom and co2 is coming out of solution. I would add a fan blowing cold air from the bottom to the top and see if it helps

 

I am currently serving at ~38 F and carbonating at 10 psi on all three kegs. All the lines are internal so temperature differential should be minimal. Yes the upper keg gets the direct cold air from the compressor but when I put a thermometer in the pint glass of beer each keg is very similar in temperature.

Beer lines are currently 15' of 3/16" ID. I started with 5' and kept making them longer. I have tried some many variations usually around 8'.

Upper keg is about 12" above the taps and the lower kegs are about 18" below the taps. The extra beer line is coiled in the door hollow space.

What I am seeing is a small stream of bubbles flowing away from the tap and back towards the keg after I close the faucet. By the time I pour the next beer (the next day) I can see several pockets of dead air or CO2 in the line in between the beer segments. These come out of the tap as glugs of foam. the remainder of the pour (actual beer) comes out smooth.

I took apart the taps and cleaned them thoroughly, lubed the o-ring in the handle in case it was letting air back into the system. I'm not sure if this is possible since I should have positive pressure forcing fluid forward but who knows?

 

Your carbonation and serving are the same, correct?

I agree, positive pressure will not allow air to be pulled in through the tap.

Maybe the source of the CO2 coming out of solution is the cold beer reacting to a warm tap. Or coupled with a tap having some kind of internal discontinuity that serves as a nucleation point that eases the CO2 out of solution.

What ambient temperature is your fridge subjected to? Is this happening for all three taps or just one, or two?

 

Does the problem change taps if you switch the location of the two kegs and keep the same tap on the same keg? If the problem stays with the keg/line/tap combination then I would investigate the o-rings on the dip tube and the out post. Otherwise I would look at the temperature difference between the upper and lower keg as a next step.

 

all three kegs are pouring at 38-F, plus or minus a degree. All three kegs are carbed through the same manifold at 10 psi. All three taps pour a few glugs of foam; I don't think it is specific to any one line.

I did notice that the CO2/air bubbles are collecting at the highest point of the coil of extra hose. I just don't know what the source of the bubble is. Maybe if I can reroute the hoses to be more level it won't allow the bubble to collect in one place.

 

Make sure all connections are tight. Do you have hose clamps on both sides of the hose? I was having similar issues and it appears it was because of the connections not being completely air tight. I had dead spots in the lines also with the taps that were foaming real bad. Not sure about the keg height thing that might also be an issue.

 

Are your liquid lines coiled up above the keg's liquid level or below? I'd try coiling them below the kegs. All of my extra line length is on the floor of my fridge. Just a thought.

 

Update: kegging system is still a disaster - pours 3/4 glass of foam.

Here's what I've tried. Added hose clamps to both end of each of the three hoses. Still foams. Coiled the extra hose at the bottom of the door (below keg post height). Still foams.

Fridge is in the garage - probably 90-95F. No reason to believe warm taps are the issue.

Disconnected beer line immediately after pouring beer, then reconnected prior to pouring next beer. Foaming is noticeably reduced; and no visible CO2 bubbles in the line. Not a practical long-term solution, but a clue.

If I pour another beer immediately after the first one, the is very little foaming.

I'm at a loss of what to try next....

 

Your taps are definitely too warm if they're in ambient of 90-95 degrees. Unless they're dripping perspiration that is. My first pour is usually half foam if the garage is warm. Then every pour after is fine. I need to add a fan to circulate the air in my keezer. Do you have a fan that is always on?

I seem to remember reading somewhere that too long of lines can cause the CO2 to come out of solution and that's what you may be seeing here. Have you tried shortening the lines a bit? I run 6' lines at 10lbs but my taps are above my kegs.

That's the other thing too - you may need to run different lengths since two kegs are below the tap and one is above it.

Good luck!

 

Force carbonation or Set and Forget? Usually air in the lines, or at least in my experience is due to your pressures not being balanced. You want to have your keg carbonated at the same pressure as you are going to serve at or else CO2 will go in or out of solution to even out. I use Set and forget of 40 degrees and ~12 psi with 10 foot lines and my indoor keezer does not foam at all. With the warm taps you most likely want some sort of fan in the keezer to blow the cool air on the shanks which should help. Then you may consider slowly upping the pressure at the regulator until you no longer see bubbles forming in the lines.

90 degree ambient can definitely cause this as CO2 will come out of solution for the first pull if the taps are too warm.

Also, I would not shorten the lines.

 

??? I would bet this is the primary reason for your issue. The heat is transfering through the metal tap, warming the beer adjacent to the tap and forcing CO2 out of solution. I would think that the forward sealing faucets could exacerbate the situation by actually putting more beer in contact with the metal of the faucet and further out into the ambient air.

 

so the problem is likely two-fold, and I agree that warm taps are PART of the problem. But the first glug of beer will cool the taps to the liquid pressure. Also the shanks and lines are inside the fridge so they will be 38 F

I am most concerned with the bubble of CO2 that grows by the hour between uses. I don't think that would be caused by a warm tap, since the bubble is not an efficient medium for heat transfer. AS I said when I disconnect the line between pours the foam is noticeably reduced.

I'll pour a beer tomorrow morning when the garage is near 75 F and note the foam level (in the name of science!)

 

That really sounds like an air leak. Double check the fittings.
The other things I would do is lower serving pressure to 8 lbs.(remember to relive keg pressure)
and re-try the shorter hose lengths.
Also make sure your gauge is working right.

 

If looking at the lines do the bubbles seem to be coming from the keg and QD's or from the tap side? Where in the lines are the bubbles collecting? This can show what side of the system the problem lies in. If you have bubbles entering the lines from the keg side I would guess that the problem is overcarbonation. If tapside I would say temperature.

On the other hand, if the problem is the tap temperature, you will have more foam when it is connected because the CO2 coming out of solution would raise the pressure in the lines displacing the beer and give room for more CO2 to come out of solution. Remember carbonation of beer is CO2 pressure and temperature. Raise the temperature and it takes more pressure to force it into solution (or keep it there).

 

Air is not going to enter a pressurized tube. It's CO2 coming out of solution, there's really no other possibility since it's starting at the faucet (at least I think that's how you're describing it). Beer (water) is incompressible, so when you disconnected the QD from the keg (and eliminated the relatively large headspace in the keg from the vapor/liquid system) you just made it so that only a tiny amount of CO2 needed to come out of solution to created enough pressure to re-equilibrate at the warmer temp.

Since this happens when the beer is static, it has nothing to do with hose length.

This is almost certainly caused by temperature stratification, especially since it's in a hot garage. The faucets and shanks are probably significantly warmer than the bulk of the beer, and chances are the beer in the line is warmer as well. The fact that it's only your first pour that's foamy is confirming this 100%.

Like others have said, you need to put a fan in there that runs 24/7. This is as simple as a $5 12V PC fan, an old DC wall wart, some L-brackets or even zip ties to secure it to the fridge, and 10 minutes of your time.

If you grab the faucet, does it feel cold to the touch? Not cool, but cold. If not, this is the problem. Depending on your humidity there should be tons of condensation on it as well.