I just started kegging. I have a beer in a 5 gal ball lock keg. I connected the regulator, set pressure to 15 psi and connected the gas line to the keg.

When I connected the liquid line (standard picnic attachment: http://www.austinhomebrew.com/product_info.php?products_id=1271) beer immediately began spewing from the faucet. After disassembling and reassembling the faucet, this didn't happen again.

I also noticed that some beer flowed into the gas line. How did this happen? Did I overfill the keg?

Will this damage the regulator?

2 Answers 2


I can't tell you how many times I've hooked up a picnic tap with it in the locked-open position :)

But yes, it does sound like you overfilled the keg. That's the only way beer can come out the gas-in post. The gas-in diptube is quite short, but I still like to give it an inch or so of space just to make sure beer can't get back into the diptube.

It will damage the regulator if the beer gets all the way up to the body. There's a fiber washer inside that seals things, and it will get saturated with beer (see my picture below). Even if it doesn't leak, it's terribly unsanitary. Make sure to replace the CO2 lines as well.

Most regulators and CO2 distribution blocks today come with check valves in their shutoff valves, like these from Midwest supply. I do recommend them, as the results of getting beer flowing back into your regulator are messy, to say the least. Not that I'd know or anything...

enter image description here

But hey, at least now I know how to disassemble a regulator!

  • 1
    I'm not ruling out operator error on the picnic tap. I'm guessing that cutting off the gas caused pressure to be higher in the keg than the tube. My regulator has a shutoff valve like that, and the tube was pointing down, so I think the regulator is OK. As difficult as it is to see inside a keg, how do you tell when to stop filling?
    – jcs
    Commented Mar 2, 2012 at 3:18
  • Honestly I just look inside the keg as it's filling. There's a welded seam near the top of the keg that's pretty obvious - I usually stop there. If you have a little flashlight (one of those small Maglights would be perfect - or wear a headlamp) it'll help you see in there too.
    – JoeFish
    Commented Mar 2, 2012 at 16:07
  • Lower pressure in the supply than in the keg can also do this. I've seen this happen when kegs have been over charged to force carbonate, and an inline valve is being used to do this. When the supply pressure is subsequently reduced, and the inline valve is released before purging the excess pressure in the keg, beer races back up the supply line. The other time I saw this happen was where the pressure was equalised throughout the system, but the line from the regulator was lower than the keg, and the keg laying on it's side, allowing the heavier brew to make it's way back down the line.
    – S.Robins
    Commented Sep 11, 2018 at 7:33

I think that most everybody who has kegged has had this happen, maybe just part of the learning curve i guess. I went to my local homebrew supply and got a check valve like joeFish was talking about (less then $10) and it puts my mind to ease, i think a new regulator is $60- $70 so well worth it. I put the check valve on the ball lock end with a small length of tubing between just so i can see if there is a problem or not.


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