Author Topic: Too much foam  (Read 7899 times)

Offline gmac

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Too much foam
« on: February 12, 2011, 03:46:38 PM »
I know this has been on here before but I can't find it.  I put 5 gallons of pale ale into a keg on Thursday and had a few last night and they were perfect but today, when we have company over, all I'm getting is foam.  The pressure is probably a bit high but I've lowered it and let off the pressure on the keg.
Any thoughts how to get rid of the foam quickly?
Thanks

Offline gsandel

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Re: Too much foam
« Reply #1 on: February 12, 2011, 04:30:55 PM »
Well, serving at a high pressure would do it if you didn't have hose lengths to balance it....also the temperature of your beer.could be a factor....did you open the keggerator a lot?  I had problems with my system foaming above 40 degrees...also my first half pint is usually foamy until the shank and faucet are cooled to the temp of the beer deep in the freezer.
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Offline tschmidlin

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Re: Too much foam
« Reply #2 on: February 12, 2011, 04:31:15 PM »
For now I think you just want to pour it into a pitcher and let it settle.  But you could vent, shake, vent, shake, vent, shake, and eventually you'll get enough CO2 out of solution to get a good pour.  The more pints you drink first, the more headspace there will be to get CO2 out.

For a slower method, turn the pressure off completely and let it sit.  If you need to fill a pitcher, just put enough pressure on it to get beer out, then vent the keg when you're done to let CO2 keep coming out of solution.  It will eventually normalize and be fine.

That's the easiest fix IMO, unless you feel like cutting a new line and replacing it with a longer one.
Tom Schmidlin

Offline gmac

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Re: Too much foam
« Reply #3 on: February 14, 2011, 05:12:52 PM »
Thanks to both of you.  I don't think temperature is the issue, the beer is in our cold room that is vented to the outside and is about 32-34 degrees.  We've had some stuff freeze in there so I don't think that's it.

I let a lot of pressure off but what I am finding now is that I get about a glass worth of clear beer and then the foam starts.  Sort of like the foam has risen off the bottom just enough to give us that much beer.  
Help me understand the dynamics.  How does the length of hose help with this?  The beer comes out of the keg as foam and travels the length of the hose as foam.  If the hose was longer (it's about 5 feet right now), would it break down into beer by the time it got the tap?  
I know the initial problem was too much pressure at the beginning but I'd like to understand more about what is going on in there so I don't repeat the problems next time.
Thanks
Graham

Offline gsandel

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Re: Too much foam
« Reply #4 on: February 14, 2011, 08:25:45 PM »
I am going through the same learning curve, so I am no expert....but, if I can explain my understanding, maybe we can learn together.  The amount of CO2 that gets absorbed into the beer is a function of pressure and temperature, so for any given pressure and temperature, only so many volumes of co2 will be absorbed in the beer.  There are a number of sources that give you a chart for temp versus pressure, but one of the best resources is the Brewer's Association Draft Quality Manual (it is on this site or the BA one).  When the beer leaves the keg, the CO2 rushes to leave the beer because the pressure outside of the keg is less than the pressure inside the keg.  At the same time, the beer that was in the keg also starts to warm as it leaves the keg.  In my system it needs to cool down the shank and the faucet.

The pressure in the keg is equal to the pressure set by the regulator (as the CO2 is absorbed in the beer).  When the faucet is opened the beer flows as the pressure escapes from the keg.  As it is escaping from the keg, it also is escaping from the beer.  The length and type of the hose is used to counter this pressure coming out of the keg and beer and in effect slow it down.  So for every type of beer hose, there is a resistance factor.  For 3/16" beer line (the stuff I use and is common for us homebrewers with short runs), the resistance is somewhere between 2 and 3 psi per foot of hose.  So, if you are carbonating and serving beer at 15psi, you would need somewhere in the order of 5 to 7 foot of hose to balance the system.  Too short a hose, and all you will ever get is foam, too long of a hose and the flow slows down to a trickle and stops altogether at some length.

You also need to take into account the height of your faucet above the level of the beer (0.5 psi per foot of height of faucet over beer, or measure an average from the center of your keg).  Also altitude plays a role.  It takes an additional 1 psi per 2,000 feet of elevation to maintain the pressures in the kegs (I am at over 5,000 feet, so it makes a difference, but I am unsure if that adds hose or takes it away in the calculation..some expert please chime in).

So, the right length of hose will give you a nice pour based on all the variables discussed.

Also, it also occurred to me that the dynamics of my system changed just before my keg kicked (was empty).  I was getting more foam at the end of the keg....not sure if that is a contributing factor for you.

I find that my system takes slightly more length of hose than I originally calculated, and improved when I bought a longer length and trimmed a foot at a time until it seemed good.

I hope I explained it accurately and perhaps was helpful.  Good luck, and let us know how it turns out.
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Offline tschmidlin

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Re: Too much foam
« Reply #5 on: February 14, 2011, 11:14:04 PM »
You get good beer first, and then it starts foaming?  Weird.  What is the temperature of the beer in the keg, is it warmer than the tap?  It's possible that the first beer is fine because everything is so cold it is holding the CO2 in solution, but that would be the first time I've heard of that.

What typically happens when your beer line is too short is like what is described above - when there is not sufficient restriction in the line, the CO2 comes out of solution before it gets to the tap and you end up pouring only foam.  By adding more restriction, typically with a longer line but a smaller ID line works too, you increase the overall restriction and it keeps the CO2 in solution.  This is the way I explain it to myself anyway.

If it is pouring correctly, you will see only beer in the line from the keg to the faucet.  If there is foam right out of the keg then the line is either much to short for the serving pressure or there is something in the way - like a dirty valve/dip tube or there might be something blocking the end of the dip tube.

So look at the line from the keg to the tap and see where the foam starts.

If you do think it is the line being too short . . .
So for every type of beer hose, there is a resistance factor.  For 3/16" beer line (the stuff I use and is common for us homebrewers with short runs), the resistance is somewhere between 2 and 3 psi per foot of hose.  So, if you are carbonating and serving beer at 15psi, you would need somewhere in the order of 5 to 7 foot of hose to balance the system.  Too short a hose, and all you will ever get is foam, too long of a hose and the flow slows down to a trickle and stops altogether at some length.
This is the correct calculation.  The 3/16" line I use that I got from morebeer is rated at 2.2 psi restriction per foot, however in my experience, on my system,  it is more like 1.6 - 1.8 psi.  I don't know why, maybe it's batch variation, maybe it's that the tops of my kegs are roughly level with the faucets, like I said, I don't know.  But at 15 psi I need about 9 feet of line to get a decent pour.  I mention this because this is totally true:

I find that my system takes slightly more length of hose than I originally calculated, and improved when I bought a longer length and trimmed a foot at a time until it seemed good.
Start longer than you think you should, even much longer.  It will save you some headaches.
Tom Schmidlin

Offline gsandel

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Re: Too much foam
« Reply #6 on: February 15, 2011, 07:40:39 AM »
Quote
The 3/16" line I use that I got from morebeer is rated at 2.2 psi restriction per foot, however in my experience, on my system,  it is more like 1.6 - 1.8 psi.  I don't know why, maybe it's batch variation, maybe it's that the tops of my kegs are roughly level with the faucets, like I said, I don't know.  But at 15 psi I need about 9 feet of line to get a decent pour.  I mention this because this is totally true:

I find that my 3/16" lines calculation at about the same 1.5-1.8 per foot....my keg tops are about 1/2 foot lower than tap, and live above 5,000 feet.  I currently have 8 foot of hose, but need slightly longer (set at about 12-14psi now) so my experience is similar.
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Offline phillamb168

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Re: Too much foam
« Reply #7 on: February 15, 2011, 07:49:10 AM »
You get good beer first, and then it starts foaming?  Weird.  What is the temperature of the beer in the keg, is it warmer than the tap?  It's possible that the first beer is fine because everything is so cold it is holding the CO2 in solution, but that would be the first time I've heard of that.

This happens to me on one of my lines. It's because of a bad installation of a ball-lock connector on the end of the draught line. I need to fix it one of these days (figure there's a tiny kink or crack or something that's causing turbulence). What happens for me is that I start to pull a pint, it comes out fine (because what's in the line is past the point of turbidity (?)) until 'fresh' beer starts getting dispensed. After that it will continue to pour foamy on subsequent pints, until I stop for a bit.

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Offline maxieboy

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Re: Too much foam
« Reply #8 on: February 15, 2011, 07:53:03 AM »
The specs and components of your system would be helpful. Maintaining a constant temp will eliminate a variable.
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Offline gmac

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Re: Too much foam
« Reply #9 on: February 15, 2011, 09:28:34 PM »
Well, I crashed the pressure down to nothing and got most of the CO2 out of solution.  In fact, it's a bit flat right now.  I'm running the pressure at about 10-12 PSI right now and I'm going to creep it up just slightly.  I had the pressure so low on the keg that I could just get beer out and that was about all.  I turned it up last night and the beer is perhaps slightly more carbonated than it was yesterday when it was sort of flat.  I'm more than happy to run comparative tests every day...

At this pressure, I'm not getting the foam that I was before but the beer is a bit flat so I think that as you've all mentioned, the hose is too short and I'm balancing the system by reducing the pressure to the point that matches the hose length.  Now, I need to change it so that I balance the hose to the proper pressure.

To answer questions asked, the tap, keg and everything else are all at the same temperature.  I have to apologize that I can't give you better information but I'd say the temperature is about 34 degrees.  You wouldn't want to stand there too long in your shorts...

Offline liquidbrewing

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Re: Too much foam
« Reply #10 on: February 22, 2011, 06:31:30 PM »
I saw in one of your posts that you are getting foam from the keg when you pour.  Last year I had a piece of a hop pellet get stuck in the out poppit.  Not saying that's what it is but, that's exactly what was happening to me and that was my problem.  Just depressurize the keg, remove the disconnect and poppit, cover the threads with some sanitized aluminum foil and inspect the poppit.  When you're done, hopefully you've resolved you issue, re sanitize everything and hook it back up.  Let the beer chill down, cuz now you will really get foam!!   

This happened to a buddy of mine a few weeks ago too. 
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Offline gmac

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Re: Too much foam
« Reply #11 on: May 03, 2011, 08:15:22 AM »
Just some follow up...
I bought 4 kegs and this was the first one I used.  I washed it and used it a second time and had the same problem.  I cleaned and sanitized a couple more and the first thing that was immediately obvious was the flow rate of the newly cleaned ones.  The sanitizer was flying out of them compared to the first.  There was clearly a significant impediment to the flow.  So, now I will tear down that foamy keg and see what I can find.  I don't have a diptube brush but I'll have to get one.  Just a bad coincidence that the first one I grabbed out of the four was the one with a problem.
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Offline Beer Monger

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Re: Too much foam
« Reply #12 on: May 03, 2011, 08:18:18 AM »
Just some follow up...
I bought 4 kegs and this was the first one I used.  I washed it and used it a second time and had the same problem.  I cleaned and sanitized a couple more and the first thing that was immediately obvious was the flow rate of the newly cleaned ones.  The sanitizer was flying out of them compared to the first.  There was clearly a significant impediment to the flow.  So, now I will tear down that foamy keg and see what I can find.  I don't have a diptube brush but I'll have to get one.  Just a bad coincidence that the first one I grabbed out of the four was the one with a problem.
Thanks

I consider a diptube brush essential.  I also remove the diptube from it's mount and place it in the keg when I'm sanitizing (I usually take my keg fittings off when I sanitize).  Then I push some sanitizing solution through the keg & out the diptube once everyting is all back together. 
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Offline euge

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Re: Too much foam
« Reply #13 on: May 03, 2011, 08:23:03 AM »
I take a piece of line and tie a scrap of damp cheesecloth to the end. Then I pull it through the tube. Mirror shine on the inside.
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Offline SpanishCastleAle

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Re: Too much foam
« Reply #14 on: May 03, 2011, 08:29:06 AM »
You might want to just swap the diptube, post, and poppet with sanitized known good ones from another keg (if compatible).  Then find the problem and fix at your leisure.  But I agree that this really points to blockage in the out line/post of the keg.