So I am getting ready to carbonate my first keg! But I am worried about beer entering the CO2 line if I use the 'rock on my lap like a baby' method :)

I am worried because I tried to carbonate a bottle of water to test my setup using one of the carbonating bottle caps. So I held the bottle sideways and gave it a good shake. But I then realized that water went into the CO2 line. Would this happen if I carb my keg while rolling it around on its side??

Thanks for any help!! Rob

  • what was the pressure set to when you carbed the bottle of water?
    – mdma
    Commented May 17, 2013 at 15:21
  • Initially around 10psi but then I turned it up to about 25-30 psi.
    – Rob
    Commented May 17, 2013 at 15:30

4 Answers 4


You should have a pretty good pressure buildup to stop liquids from coming up the line; although that won't stop excessive shaking from overwhelming the pressure in the gas line.

Odds are you have a directional flow valve on your regulator, so you don't have to worry about gas being pushed back. You probably shook the bottle of water hard enough to overcome whatever pressure you had on the gas which is why you saw water coming back up the line.

If you are going to gently rock the keg, you will most likely be fine. I have never had a problem. Although if you want to be doubly safe, you can put a check valve in line on your CO2 line which will prevent any liquids from coming back up the line. At the very least this will stop the liquid from passing the check valve.

  • 1
    Check valves like this one are very inexpensive protection for your regulator.
    – bughunter
    Commented Oct 8, 2014 at 12:03

The only time I had liquid enter my line was when I had the gas tube on the bottom, keep the gas tube at the top when you rock and roll and you'll be fine.

  • I rock my kegs back and forth about 20 degrees from a standing position. You will be able to hear the CO2 being pushed into the keg as it is absorbed. When you hear that, you know you are creating enough agitation. If you are not in a hurry, you can just set it at 30PSI and let it sit for 24 hours.
    – jalynn2
    Commented May 17, 2013 at 17:37
  • you should also see the low pressure change move down as it absorbs the CO2. When you stop rocking it'll slowly go up. Also, the keg will feel colder.
    – Doug Edey
    Commented May 17, 2013 at 18:04

While it's possible for some to go in that direction, there should be some pretty good positive pressure (especially when it's pumped up for carbing w/ shaking) to prevent anything from going upstream.

If your system is designed well, the valves will have flow restrictors that allow only gas to leave the regulator... aside from whatever might get stuck in the tubing there's no problem. I've personally never noticed anything go into the gas side during shaking.


Get a gas connector that has a built in check valve.

I.e get this: http://www.williamsbrewing.com/GAS-BALL-LOCK-FITTING-WITH-CHECK-VALVE-P3358.aspx

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