Too much carb - possible causes?

Trying to track down my problem. Kegged an IPA a couple weeks ago. Set it at 15psi (cold, ~38degs) for about 4 days before I could not keep myself from pouring a pint. Result was 1 inch beer, 5 inches foam. (Serving pressure reduced to about 2.5psi).

What I notice is that, since the beer line is clear, I can see that as the beer exits the keg, it has large bubbles in it, at times it even surges or spurts through the line. I thought the tube might be clogged, but I pulled it out and it isn't. My next two theories are:

Bad post/poppet?

Overcarbonation?

Lastly, I discovered this morning that I apparently have a leak in the system as my regulator tank guage showed about 1000 psi on Tues nite and now shows less than 500. Could a leak cause foaming?

Over-carbonation, 15 psi is very high for an IPA. After you've pulled 5-6 pints, things should settle out.

Tank pressure - did the temperature change much during that period? The primary pressure has nothing to do with how full the tank is, until it goes below ~300 psi. At that point it's running on fumes.

Well, the pressure in the tank varied from about 1000psi to 500psi. On my tank guage, the "red zone" is from 0 to 500psi. When should I look at refilling?

As for the over-pressuring, I've taken all pressure off the keg now and I've been purging it for a about a day and a half hoping to relieve some of the carbonation.

Guidry said:

Well, the pressure in the tank varied from about 1000psi to 500psi. On my tank guage, the "red zone" is from 0 to 500psi. When should I look at refilling?

As for the over-pressuring, I've taken all pressure off the keg now and I've been purging it for a about a day and a half hoping to relieve some of the carbonation.

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The best way to handle the 1000 psi to 500 psi on the gauge is to simply cover it with duct tape. It's useless as a "gauge" to see how much gas is in there. Since co2 is a liquid that is dispensed as a gas, it will read 500 psi in a fridge but 750 psi at room temperature. It will stay at those pressures until there is almost no co2 left at all, then it will go to 0. The only way to really know how much co2 you have in the tank is to weigh it. Then you subtract the tare weight stamped on the tank and the weight of the regulators, and you'll know how many pounds of co2 you have left.

Anyway, the reason that it's sputtering and stuff is due to the change in the pressure- from 15 psi to "serving pressure" means that the co2 will come out of suspension as it's poured. I'd reset to the correct carbonation pressure (probably 11-12 psi at fridge temps) and keep it there. Longer serving lines will stop any foaming- mine are 10' of 3/16" ID line.

Foam does not necessarily equal overcarbed. I could undercarb something and then run it through warm lines and get tons of foam too as co2 comes out of solution. I could also have a 1' serving line and it will also spit co2 out of solution since there's not enough resistance.

How long are your lines? Is this a picnic tap or kegerator or something else?

I have 10' 3/16" lines with a picnic tap.

"The best way to handle the 1000 psi to 500 psi on the gauge is to simply cover it with duct tape. It's useless as a "gauge" to see how much gas is in there."

Well, crap! Here I thought my the guage would help me. Oh well, at least I'm not deviating from my ways of learning the hard way.

Like Yooper said, your serving pressure needs to match the carbonation level. If you serve at a pressure lower than what equates to the carbonation level, gas will come out of solution causing foam, and you'll slowly lose carbonation with every pour until it reaches the level that equates to your lower pressure (2.5 psi and 38° = flat beer BTW). If you use a higher serving pressure, the carbonation will increase until it reaches equilibrium with the new higher pressure. Use a chart like this one to determine what you need to keep your serving pressure at.

Guidry said:

Well, crap! Here I thought my the guage would help me. Oh well, at least I'm not deviating from my ways of learning the hard way.

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It does help, just not nearly as much as you thought it would. When it reads at or below your serving pressure it's empty. When it reads over ~300 there's at least some gas in the tank, but who knows how much. When it reads between 0 and 300, you probably only have enough gas left to pour a couple beers.

Well, I solved my issue last night. I had been purging the beer for two days, but when I tried to pour a pint last night, it still came out in spurts with large bubbles in the line. I tested all connections for leaks with starsan sprayed on them. No bubbles, even upon very close inspection. It really looked like to me that gas was being introduced into the fluid stream somewhere above the fluid level in the keg. My next idea was to switch out the post with a spare, maybe there was an internal leak. After I removed the post, I had the idea to switch around the in/out posts and tubes completely. I recalled that the bottom of this keg (used/rebuilt) does not have a regular semi-sperical bottom. There is sort of a trough leading from the center to almost the edge in one direction. Appears to be a way to drain more fluid out (just guessing). The "out tube" is also curved, so I thought MAYBE the combination of the post location/trough/tube shape is not lining up right. I switch them and tried again. The pour immediately changed from spurting to a smooth almost damn near perfect pour. At 2.5psi, I got about a 1/2" head on the pint. I figured a little more pressure over a day or so and it may get a little better....Even if it doesn't, I can certainly live with that kind of pour anytime.

That's great to hear! Remember that at 2.5 psi the beer will start to go flat as it seeks equilibrium so once it's not overcarbed, make sure to turn it back up to 11-12 psi.