Full keg to carbonate?

[Maki_bOo]

Hello,

I'm about to keg some 7.5 and 15.5gal kegs and I just had a sudden question. Can I actually put 7.5 and 15.5 gallons of beer and then carbonate it? or do you have to leave space or something for forced carbonation to ocurr?

 

[Mark Farrall]

If you're planning to use a shaking method to speed up the carbonation headspace will help that.

Or if you fill through the top and manage to fill to the rim, you'll create a bit of headspace putting the lid on.

If you do a closed transfer I always find it spewing beer out the pressure release valve when I release it and stop then. I'm sure I've still got headspace left at that point.

Saw this a while ago and thought it may let me get more in the keg.

Still it won't be a lot of beer left over if you do try to fill it as much as you can, regardless of the method.

 

[J A]

The kegs will have

If you do a closed transfer I always find it spewing beer out the pressure release valve when I release it and stop then. I'm sure I've still got headspace left at that point.

Are you transferring into the "out" post? If you're pumping beer into the in post, it drops to the bottom and foams up a lot. When it goes through the pickup tube, it stays calm and doesn't foam out. I transfer carbonated beer this way all the time and almost never have any foaming out the pressure release.

 

[Craigerrr]

What JA said!

I wouldn't think that you would need much head space, as long as the surface of the beer is exposed the C02. Pressure is exerted equally across the surface. For instance when the keg is 3/4 empty the carbonation level does not increase. I do the following to speed up the process. Some rock and roll the keg during a similar process.

Once I transfer in through the dip tube, I then hook up the gas to that same side. With the regulator set at about 5#, the little ball valve after the regulator closed, and the relief closed I gradually open the little ball valve after the regulator and let the C02 in slowly, and let the pressure equalize. I then turn off the little ball valve, slowly release the relief valve, and repeat. I do this 4 or 5 times. I use to let the gas rush in, but it would froth up and make a mess when I released the pressure. After this process I set it at 25# and leave it for 1-2 days, then it is ready to serve.

 

[Maki_bOo]

Thank you everyone, I made the density calculation to make sure the kegs were full depending on the beer and then I forced carbonate normally and everything went perfect ash you mentioned, no need for extra space.

 

[J A]

If you have a lot of headspace, the carbonation will occur faster. It has to do with the volumes of CO2 at pressure. If you have approximately 1/10 or so of keg volume in empty space as you would with a full keg as opposed to 1/2 of the keg volume in empty space in a half full keg, the amount of CO2 at the same pressure will be much larger with the half empty keg. That means there's more CO2 available to enter suspension.
That differential is no longer a factor if you leave the CO2 hose connected at high pressure throughout the process, though...for instance 30# pressure overnight. It shouldn't matter at that point the level of the beer in the keg.