kegging and carbonating

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balto charlie

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Hey folks: I put 2 kegs under CO2 at 15-20 PSI. I then pulled them off of the CO2 and returned the CO2 line to the lines I was drinking. 2 weeks later(yesterday I tapped them and they were flat. Do i need to keep the CO2 line attached? OR attached routinely to addd some more CO2?? Or should I check for leaks. One keg might have had a slight leak(checking that out) but the other still was under pressure but no longer 15 PSI. They haves been 2 weeks @ 45F. Thanks guys. Charlie
 

Blender

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I am not real experiened with kegs yet but you do need to keep them on the gas to carbonate. After they are carbonated it may be possible to pulll them off for awhile and still maintain the CO2.
 

cubbies

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Yes, you definitely need to keep CO2 attached. I am neither a scientist, nor a teacher, but I will do my best to explain the circumstance:

When you put CO2 pressure on the keg, the CO2 build up in the free space above the beer. Eventually, some of this CO2 will precipitate into the beer. However, at the same time, the beer is also emitting CO2 (think beer in a glass with the bubbles coming up). Eventually an equilibrium is reached and there is too much C02 in the headspace for the beer to release it's CO2; thus the CO2 stays in the beer creating carbonation. However, as you pour beer, the headspace in the keg becomes larger and larger. If you do not have CO2 attached to the keg, the equilibrium between the CO2 in the beer and the headspace is broken, allowing the beer to release it's CO2 into the headspace. Eventually, there will be enough headspace (and not enough CO2), where the beer is able to release all of it's CO2 into the headspace and thus causing flat beer.

So, very long story short, you have to keep it attached to the CO2, or at the very bare minimum, hit it with a CO2 blast every 5 or so pints. I would recommend keeping it attached.
 

DraconianHand

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Sounds like you probably have a leak.

Once you put the keg under pressure it should maintain pressure. If you carb at room temp and then store them at low temperature, you should see a drop in pressure, but it shouldn't be an incredibly large drop.

I carb my kegs at 68*F, 30psi. Then I store them at 32*F until I am ready to serve them, sometime for months. Even with a 36* temperature change my beer is still WAY overcarbed.
 

DraconianHand

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cubbies said:
When you put CO2 pressure on the keg, the CO2 build up in the free space above the beer. Eventually, some of this CO2 will precipitate into the beer. However, at the same time, the beer is also emitting CO2 (think beer in a glass with the bubbles coming up). Eventually an equilibrium is reached and there is too much C02 in the headspace for the beer to release it's CO2; thus the CO2 stays in the beer creating carbonation. However, as you pour beer, the headspace in the keg becomes larger and larger. If you do not have CO2 attached to the keg, the equilibrium between the CO2 in the beer and the headspace is broken, allowing the beer to release it's CO2 into the headspace. Eventually, there will be enough headspace (and not enough CO2), where the beer is able to release all of it's CO2 into the headspace and thus causing flat beer.

So, very long story short, you have to keep it attached to the CO2, or at the very bare minimum, hit it with a CO2 blast every 5 or so pints. I would recommend keeping it attached.
Cubbies,

I think you have misread the OP (or maybe I have). It appears that Charlie is carbing the beer, storing it and when he goes to tap and serve, he finds it flat. Sounds like Charlie is keeping his serving kegs on CO2.
 

Zymurgrafi

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If you only pressurized it for a few minutes @ 15-20lbs. and then removed it, yes it will be flat.

If you "force carbonate" it fully then remove the gas, it should still be carbonated when you tap the keg. So, say you want to carbonate and then store it in the fridge but not keep it under pressure. There are several ways to do this. Leave it about a week at serving pressure and temperature with the gas on then diconecct and leave it cold (gas comes out of solution faster at high temps) or, put it at 20-30lbs. for about 24 hours shaking every now and then. The shaking helps dissolve the CO2 into solution faster. Careful with the later method though. If you aren't attentive you can easily overcarb.

It takes time irregardless to carbonate because the gas has to be dissolved and absorbed into the liquid. The one blast you gave it was absorbed but it was not enough to be percieved as carbonation.
 

cubbies

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Ah yes, I suppose I did misread. The first line is what confused me. He did carb and then detatch the line, but apparently his first tap was flat (I love it when brewing related stuff sounds naughty heh heh).

I guess I thought as he was drinking it eventually got flat.

Ignore my original post.

Oh, and yeah, +1 on a leak somewhere.
 

Blender

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DraconianHand said:
........I carb my kegs at 68*F, 30psi. Then I store them at 32*F until I am ready to serve them, sometime for months. Even with a 36* temperature change my beer is still WAY overcarbed.
How long do you leave the kegs at 30 psi? I always thought it had to be maintained for period of time and then one could disconnect the keg and keep the carbonation level.
 

Bobby_M

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I don't think anything was misread at all. The OP wasn't clear. All that was said was "I put 2 kegs under CO2 at 15-20 PSI. I then pulled them off of the CO2...". There was no indication of the time that had lapsed between the two steps. I THINK he just put 20psi on the keg and immediately disconnected. Equilibrium was probably reached as something like .2 volumes (i.e. flat).

Pressure has to be maintained the whole time the beer is taking co2 in. It can then be stored off the gas but must be returned when you want to dispense so that the new headspace is replenished.
 
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balto charlie

balto charlie

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OP reporting: sorry if I was unclear. I kegged beer that was at 65F but then put into the "cold" room(45F). This is where I put them under CO2 to 20 PSI, shook them, heard more gas going in, then turned off the CO2 when they reached 20 psi again. I then removed the CO2 lines and put them back onto the beer I was originally drinking.
Last night after discovering this I re-pressured them to 20PSI, shook repressured to 20 PSI. I did this 3-4 times over the time it took for my Terrapins to lose to Duke and tune up my bike.
There really seems to be a difference of opinion here. I'm confused. If i leave one tank on the CO2 and the other off we may have the answer. I am going to test for leaks tonight as well, just to rule that out.
Charlie"I hope this is better relayed to you folks"
 

DraconianHand

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Blender said:
How long do you leave the kegs at 30 psi? I always thought it had to be maintained for period of time and then one could disconnect the keg and keep the carbonation level.
Ah, looks like I too omitted this information. It usually sits on pressure for at least a week. Every time I walk past it I shake the snot out of it. Once I stop hearing the sound of CO2 going into solution, I take it off gas and store.
 
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balto charlie

balto charlie

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DraconianHand said:
Ah, looks like I too omitted this information. It usually sits on pressure for at least a week. Every time I walk past it I shake the snot out of it. Once I stop hearing the sound of CO2 going into solution, I take it off gas and store.
OK now it's all making sense. That's what I did yesterday and will continue to do until my CO2 manifold and other part arrives. Charlie
 
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balto charlie

balto charlie

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Everybody thanks for your replies. Got it figure out. Didn't get a chance to check for leaks because it was VD day. That will happen tonight. Charlie
 
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