Dispense without constant C02?

I am familiar with the different carbing methods for homebrew kegs but I have a question about serving from the kegs.

I have seen people properly carb kegs with the set and forget method, disconnect the C02 lines, and then serve with just the existing C02 in the keg. In this case, when the beer stops flowing as well as desired, do you just need to replace the new headspace with C02, or are you essentially removing carbonation from the beer when doing this, requiring you to re-carb the beer left in the keg?

My main reason for asking this is, I would like to serve from three kegs with only two kegs worth of hardware.

patricksprague said:

I am familiar with the different carbing methods for homebrew kegs but I have a question about serving from the kegs.

I have seen people properly carb kegs with the set and forget method, disconnect the C02 lines, and then serve with just the existing C02 in the keg. In this case, when the beer stops flowing as well as desired, do you just need to replace the new headspace with C02, or are you essentially removing carbonation from the beer when doing this, requiring you to re-carb the beer left in the keg?

My main reason for asking this is, I would like to serve from three kegs with only two kegs worth of hardware.

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Once the keg pressure is reduced, the CO2 will escape from the beer. It's about equilibrium. If you removed all of the pressure in the keg, the beer will go flat pretty soon. You really need to set the appropriate carbonation level and leave it at that level until the keg kicks. You can probably do what you describe if you planned on finishing the keg in a few hours.

Or if you every couple of days top up the unconnected keg to the proper serving pressure. How often you top up will depend on how quick you drain the keg, and you will have to do it more often when the head space is smaller.
I have previously primed half of a keg so that it was slightly overcarb'd and then let the pressure push out the ~2.5G that was in the keg, worked alright a bit fizzy first off but at the end it was taking a bit long to fill a glass

Reelale said:

Once the keg pressure is reduced, the CO2 will escape from the beer. It's about equilibrium. If you removed all of the pressure in the keg, the beer will go flat pretty soon.

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Not as soon as you would think. The removal of the CO2 is fairly slow. Days. Not to mention that if 'use' all the head-space pressure, the beer will lose CO2 but as long as it is sealed it will re-equilibrate. I sometimes do this....I will pull a pint (or a few) from a keg that is conditioning/aging and forget to re-hit the keg with CO2 that night. If I check it the next day, there is a slightly noticeable loss in carbonation but certainly not flat. (Note that shaking/agitating the keg will hasten this re-equilibrium as you are essentially dealing with a super-saturated solution at that point.)

That is exactly what I wanted to know. Thanks for the help.

it'll go flat, but take days. i feel that, as my co2 tank just went dead 20 minutes ago...

patricksprague said:

My main reason for asking this is, I would like to serve from three kegs with only two kegs worth of hardware.

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I thought this would be a good idea too, but found that my used kegs leaked sometimes around the poppets, so if I took the gas off, the beer might be flat next time I hook it up.

I think its worth it to price a gas distributor. I got a 3 way distributor for $30, runs off a single output regulator, and my original 2 output regulator runs 2 kegs. So I get 2 different CO2 volumes across 5 total kegs.

if your 3 kegs are brand new or never leak, you might pull off what I could not.

lumpher said:

it'll go flat, but take days. i feel that, as my co2 tank just went dead 20 minutes ago...

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It shouldn't go flat if you leave it alone, if you are drinking it and therefor causing the pressure in the headspace to decrease it will go flatter, but even at 0 PSIg there is still 1.3 volumes @ 46*f so it will be flatter but not still

I understand if you don't want to spend money on extra faucets or upgrading a tower for something you might only drink occasionally. But you're looking at $10 tops to tee into one of your lines and keep it on the gas the whole time. You could shuffle back and forth with one of your existing faucets when you want to serve (losing a couple ounces of beer each time you switch), or spend another 10 bucks on a picnic tap and just open the fridge when you want a glass.

I don't know about you guys, but shuffling CO2 and beer lines every time you want a couple of pints seems like a whole lot of trouble to go through to save a Jackson.