Carbing up a replacement keg

[codycleve]

New to the forum and did a quick search with out much luck.. I am new to home brewing and am going to keg my first beer on Wednesday.
I am building a dual keg kegerator and want to have the option of having a third beer kegged, carbed, and ready to go when one blows. I have a spare fridge out in the shop that I can keep the spare in.
My Question is, can I simply keg my spare beer and use the co2 tank and line off of my kegerator to charge it to 20 or 30 PSI, disconnect, and then move it out to my spare fridge. Or do I need to have a spare tank regulator and line that is hooked up providing continuous CO2.
I don't want to sugar prime my spare beer because it takes 2 weeks and it may not be that long before my next keg blows..
Thanks in advance for any help and sorry if this has already been covered.

 

[day_trippr]

Carbonation is best described as a volume equivalent to the beer being carbed. And a middle-of-the-road carbonation would be roughly 2.5 volumes of CO2 - meaning for a five gallon keg of beer, 12.5 gallons of CO2 at the prescribed equilibrium pressure given the beer temperature is required.

If you put exactly five gallons of beer in a cornelius keg there's roughly a couple of quarts of head space left. That's the volume you'd be filling with gas. Let's call it .5 gallons and you're carbing at 38°F, so you'd need to fill that head space roughly 25 times at 11 psi, while allowing for the beer to absorb each "shot".

You could double the CO2 pressure and markedly cut down the number of cycles (perhaps by half) but it still doesn't sound very practical.

fwiw, faced with the same situation I picked up a Craig's List fridge, a manifold and regulator, and a swap tank. Much easier.

Cheers!

 

[DaWhip]

Similar kegerator situation and I had decent success with my recent swap like this:
1. Cold crash carboy for a few days
2. purge keg, then fill it to ~5psi
3. Rack from cold carboy to keg - I use a fancy DIY contraption to push from the carboy into the keg out post at ~3psi (my contraption has built in safety - it falls apart if pressure gets much higher in carboy). keep an eye on your flow and relieve pressure from the top of the keg as needed to keep filling. It should be a pretty slow flow since pressures are matched and you are regulating them. Towards the end things got a little foamy, so I slowed way down. Just do it somewhere easy to clean up a little foam/beer spill. (search youtube for "beer transfer carboy to keg with co2" for a method similar to mine)
4. With the cold beer in the keg, I put it up to about 30psi, maybe a bit more, on the same principle that day trippr mentioned, then left the keg at room temp to age for a few weeks.

I put it in the kegerator yesterday and pulled a sample right away (warm). It had some bubbles, but not enough. I left it to cool overnight with the line hooked up at serving psi and it was good to go when I got home from work today. So not 100% immediate swap but not bad for no shaking.

I have only done this method once, so I can't make any claims to its repeatability, but I will be racking to keg in the same manner tomorrow.

 

[mongoose33]

Daytrippr gave an excellent explanation of what's happening in carbing a keg.

I do something similar to you--I want a keg carbed and ready to go when I need it. So to get it there, here's how I do it.

1. Cold crash the beer (good for clarity anyway). I cold crash to 32 degrees while it's still in the fermenter. My current routine is to add some gelatin for finings. It takes close to a day for the temp of the fermenter to drop to 32. Then I fine it, wait another day or two, then proceed to:

2. Transfer to the keg. I fill the destination keg w/ Star San, all 5-gallons worth, hook it up to CO2, purge the remaining headspace a few times, then push the Star-San out to either another empty keg or a 5-gallon bucket. The act of pushing out the Star San with CO2 "purges" the keg, leaving almost pure CO2.

3. Transfer from fermenter to keg. I do it this way as in the pic, returning the displaced CO2 from the keg to the fermenter so I'm not drawing air--and oxygen!--into the headspace of the fermenter.



4. Return keg to refrigerator to keep it at or near 32 degrees (36 is a good number, but the colder beer is, the more readily it absobs CO2). Then I hook up the gas, at 30 psi, for 24 hours. This gets me very close to what I want for carbing, you might want it a bit higher, but you'll be close to what you want, more than likely.

5. At that point I can just leave the keg sit until I'm ready to tap it, or what I often do is tap it with a picnic tap. To do that, I'll release whatever remaining headspace CO2 remains, hook up to serving pressure CO2, and go. The CO2 tank/regulator is inside the fridge along with the keg. I just open up the door and pour!

In 24 hours, once the beer is cold crashed and in the keg, you'll have drinkable beer. Some brewers use 36psi, others are trying to hit an exact carbonation schedule. Me? I don't pay quite as much attention to that as others.

*****************

There's another way to force carb it if you are out of time. Hook up the keg, in which you have the cold beer, to the gas at about 36 PSI. Rock that keg on your lap back and forth sloshing the beer inside. The increased surface area of the beer and the sloshing greatly increases the surface area of the beer into which the CO2 is absorbed. You'll hear the regulator continue to groan as it adds CO2, and you'll hear the bubbling as it enters the keg. At some point I'm going to try to quantify this, but for now, 10 minutes should get you in the ballpark.

 

[The_Bishop]

There's an even faster way to do it without overshooting.

Once you have your cold-crashed and clear beer in the keg, make sure the headspace is purged very well. Put it on 30psi, then rock it for 30-40 seconds with the gas still attached and on. I keep the keg vertical when I'm doing this to prevent beer from making it's way into the gas line. You'll hear it absorbing a lot of CO2 while you're doing this. This will handle the bulk of your carbonation.

Next, consult the temperature/carbonation chart. Once I'm transferred into the keg, I'm usually sitting at around 36f for temperature. Say I'm looking for 2.3 vols of CO2 carbonation in my beer, so that'll be 8 psi.

You can do two things at this point:

1 - Set the regulator to 8 psi and keep rock until you don't hear any more gas running through the regulator. This will get you to your target carbonation point without overdoing it.

2 - The method I'll usually use: Shut off the CO2 bottle with the regulator still set to 30 psi. Rock the keg until the pressure stops dropping on the regulated pressure side of the gauge. This will tell you your residual head space pressure, which will tell you your carbonation level. If it's below our target of 8 psi, crack open the CO2 bottle and re-pressurize the headspace, then shut it down and rock until stabilized again. Do this until you have 8 psi residual pressure showing. You are now carbed. This takes me about 5 minutes per keg and doesn't over-carbonate.

 

[codycleve]

Thanks for all the replys.. a lot of good ideas here and helpful information.. so if I had a beer finish a week or so before there was room on the tap to keep it all I would really need to do is bleed off the o2 with co2 in the keg and it will keep fine.. I'm new to all of this and learning more every day..