Continual problem with flat beer

[BrewFrenzy]

I've been trying my hand at kegging for about 8 months and have kegged 4 or 5 batches. Each has come out fairly flat. The last three batches have been slight variations on a Pliney clone extract kit from MoreBeer.

Some details:
- My beer line is 5' with a picnic tap
- My kegerator setup is about 15 psi serving pressure at around ~38-40 F.
- I use typical 5 gal. corny kegs & and brew 5 gal. batches
- I have a 5 lb. CO2 tank that is confirmed to have a good supply of gas.

Of the last three batches:
#1: was kegged at 15 PSI and left for 2 weeks in kegerator. Beer came out with a decent head which rapidly went away. Beer had minimal carbonation. I raised to 20 psi for a week, then lowered back to 15 psi... same result with a bit more head.

#2: thinking last batch was 'bad' somehow. I brewed same recipe and got same result. I didn't raise then lower pressure... just tolerated flatness

#3: brewed same recipe with slightly different steeping grains. Kegged at 15 psi for 10 days... same result (OK but quickly dissipated head, fairly flat beer). I raised to ~30 psi, disconnected from CO2, removed from kegerator, rolled back & forth on floor for 15 minutes. Re-kegged, found pressure at ~25 psi, lowered to 15 psi. Next day... huge head which stuck around for a while, improved carbonation but still kinda flat.

What am I doing wrong? And... if nothing else, would naturally carbonating in keg then using a tank to serve possibly help?

[the lizard king]

I have heard that naturally carbing in a keg with sugar sucks. I would suggest using a chart to help you figure out how much co2 you need at the time of carbonation they have them all over the internet, it has to do with the temp of the kegerator and all that good stuff. I usually carb mine for 14 days at 20 psi or so. once they get to the rator they sit at about 10 to 15 psi. I would also look into the tubing length, if your tubing is too long you will loose to much carbonation in the beer as it make its way to the tap, also my first pour is usually crappy anyway so I just toss it. I have only been doing this for a few months, and it has worked out well so far. My carbonation is pretty decent with about 1/2 heat on the beer, it goes away eventually by the first couple of sips but there is usually a nice ring that follows the beer all the way down to the last drop. and I really dont like my beer overly carbonated. hope that might of helped to some degree. there is alot of information on the web about that stuff thats were I got all my information from. p.s 3/16 id tubing is a must.

[dirtbikejunkie]

any sign that you have a leak? how much co2 are you going through? e.g., if you have done 4-5 batches and had to fill (assuming 5lb bottle) more than once you may have an excessive leak.

try doing the quick forced carb method and see if your results change (i.e. 30 psi shake the hell out of your corny)

[BrewFrenzy]

The charts I've read generally call for 2.4 volumes of CO2 at 39 F for a pale ale. I also throw away my first pours. I also have 3/16 in. tubing. While opinions vary a bit, I think anywhere from 5 to 6 feet of tubing is needed so I should be good there since I have 5 feet.

I'm pretty sure I don't have a CO2 leak. I've been really good about monitoring my tank level and it's given no indication of losing gas.

The 30 psi/keg shake did improve things... just not as much as I'd like. Barring any obvious answer, I may try more aggressive versions of that.

Another thing occurred to me... if my regulator shows a bad reading on keg pressure, I suppose I might not be getting the 15 psi I want. I guess I could just try setting it at 20, 25, or higher and see what happens. I would stop once I started getting a violent spray instead of a pourable flow.

[manwithbeers]

What is the temperature of the beer? I don't mean the temperature of the fridge, I mean the beer after you pour a glass? The force carbing charts reference the temperature of the liquid. Measure that and adjust pressure (increase) or lower the temperature accordingly. Let it sit under pressure for another couple days and then check the carbonation level. A clean chilled glass is also helpful.