Should my keg hold pressure disconnected?

Hi guys

Just a quick question. I have a full, uncarbonated keg at room temperature. I apply 20-30 psi of pressure and check for leaks with soapy water. There are none. I then disconnect the gas and when I come back a day later there is only very slight pressure left in the keg. Like a small 1 sec fizz and then nothing. Is this normal? Could I assume it is the CO2 being absorbed in the liquid, i.e. carbonation in the making?

CO2 will get absorbed, to the point where things will reach equilibrium. A point where CO2 isn't being drawn out of the liquid, but isn't being forced in.

Just from the comments you made, I can't say "Nope, no leak", but you are definitely absorbing some amount of CO2 into the liquid. Someone with more experience might know how normal this amount of absorption is.

Yes that's normal as the co2 is being absorbed into the beer as stated above. It will lose pressure until you reach the same pressure in the keg as what's set on the regulator. At room temperature it would take a considerable amount of co2 to reach balance. So unless you leave it hooked up and give it long enough to carb the beer to proper volumes of co2. So unless your leaving a fully carbonated keg off the gas and coming back to it being almost flat I'd say you don't have a leak. Just my .02 if I'm wrong I will be corrected.

Ok, thanks guys! And no problem in the lack of pressure right, as I suspect all oxygen has been purged out? There will not be room in my kegerator for another 2 weeks.

tegeberg said:

Is this normal?

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Yes. Completely normal, as other posters have noted. Liquids absorb CO2 in the headspace until they reach equilibrium.

tegeberg said:

Could I assume it is the CO2 being absorbed in the liquid, i.e. carbonation in the making?

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You should certainly not assume that!

The only way to know 100% that a keg is not leaking is to pressurize it when empty to a known pressure, then check the pressure again at the same temperature some time in the future. That's how plumbers certify natural gas lines in your home.

Most of us just go with the "good enough" method of pressurizing to 10 psi when empty, leaving it pressurized until the next use, then "burping" it just before use to make sure it held.

tegeberg said:

Ok, thanks guys! And no problem in the lack of pressure right, as I suspect all oxygen has been purged out? There will not be room in my kegerator for another 2 weeks.

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Practically all of the oxygen has been purged out if you dumped all of the headspace at least once. When kegging, I burp the pressurized empty keg, fill with beer, pressurize to 10 psi, burp the headspace back out, and fill back to 10 psi. Overkill? Probably. But one extra headspace of CO2 is cheap compared to a keg full of oxidized beer.

You'll be fine to bulk condition at room temperature. If you're trying to force carb at room temperature, you're likely going to fall short on the carbonation. Conditioning with priming sugar should be fine.

What do you mean by a one second fizz? Are you pulling the relief valve and getting that or are you hearing another fizz somewhere. Also are you meaning to leave it uncarbed, because one quick shot of 30psi wont do it, if your trying to carb it.

Yes, when pulling the valve, and no it is only left uncarbed untill there will be room in my kegerator.

tegeberg said:

Hi guys

Just a quick question. I have a full, uncarbonated keg at room temperature. I apply 20-30 psi of pressure and check for leaks with soapy water. There are none. I then disconnect the gas and when I come back a day later there is only very slight pressure left in the keg. Like a small 1 sec fizz and then nothing. Is this normal? Could I assume it is the CO2 being absorbed in the liquid, i.e. carbonation in the making?

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Yes!

tegeberg said:

Yes, when pulling the valve, and no it is only left uncarbed untill there will be room in my kegerator.

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As long as you purged the oxygen from the headspace, you'll be fine to bulk age in kegs. In fact, many brewers secondary and bulk age in kegs as their vessel of choice. I'll be moving that way once I get my equipment setup satisfactory.

At a rough guess, I think you'd be find storing a cream ale around 2 months, heavier gravity beers closer to 6 months, and something like an Russian Imperial Stout or a Barleywine up to a year at room temperature before you start to lose some flavor.

thadius856 said:

Practically all of the oxygen has been purged out if you dumped all of the headspace at least once.

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no, one purge at 10psi will get you down to about 13% oxygen remaining. the target for remaining oxygen is <1% at most breweries.

it takes four full purges at 14psi to get to 1.3-ish% oxygen. a fifth purge gets you under 1%.