Strange foaming issue

[diS]

OK, for the first time I have keg foaming problem.
System is well balanced, it is not new one, actually I made it few years ago and it served me well in the past.

I have couple of kegs that's been maturating for ~14 months so I decided its time to clear them out.
So I set them in keezer and cooled to ~40F for couple of days. First pours were great but after few days when I pour nothing but foam comes out.
I noticed that CO2 persist in beer lines so I checked for pressure, gauge is set for 9 PSI so it seems right.. beer temp. is 40F and 1/4" OD line is 7.6 feet long.
CO2 gauge is checked with another one and it is accurate, temperature of keg top where beer lines are is same as beer in keg.

I know that it could be due the pressure drop in beer lines, but I didn't changed diameter on last line replacement.

What else am I missing here, or it is just due the beer age (but then first pour would have to be problematic too.. right)?

 

[stratslinger]

I had a similar issue a few months back, and it turned out that when I had reassembled my keg after its last breakdown and washing I had forgotten to re-install the o-ring on the liquid dip tube. Could be worth a check - just purge your lines and sanitize well as you open up and break things down to check.

 

[MagicMatt]

You say that the regulator reads 9psi, but what is the pressure of the keg itself? Just because the regulator says 9psi doesn't mean that's what the keg is at. Perhaps your keg is overcarbed and at something more like 20psi?

 

[diS]

That is what I thought so I de-gassed kegs until beer was almost flat, then set CO2 and carbed it again. Same thing appears.

@stratslinger
I would have this problem right after 1st pour if there was o-ring missing, but since first few days pour was good I don't think the problem is in o-rings.

I read somewhere that cause of over-foaming could be in old beer, seems that I have to brew fresh batch to confirm this.

 

[MagicMatt]

That is what I thought so I de-gassed kegs until beer was almost flat, then set CO2 and carbed it again. Same thing appears.

I read somewhere that cause of over-foaming could be in old beer, seems that I have to brew fresh batch to confirm this.

I've served beer over a year old and there were no foaming issues. There should never be any foaming issues due to age alone, that doesn't make any sense.

As for degassing and recarbing, how did you do this? I don't see how you'd be able to completely degas a keg of beer and then carb it back to appopriate levels in such a short amount of time. To make the beer flat would take weeks of pulling the pressure relief several times daily (I know this because I'm doing it now on a Saison that continued to ferment once kegged and was at 60psi after sitting for a month. Just to get it back down to 30psi has taken 10 days of purging).

So it would take quite a while to get all the CO2 out, and then another week minimum to carbonate it correctly again.


Just pulling the pressure relief and sticking the gas line back on it will not change the carbonation level of the beer; if it's overcarbed, it'll still be overcarbed.

 

[thelastleroy]

+1 on the dip tube o-ring. Had this problem on a brand new keg. It's easy to check!