I got the liquid (black) connector very stuck on to my keg, to the point where the plastic broke when trying to pull it off. I'm guessing it's because I mixed up the little posts after removing them for cleaning. They look really similar, but I can see that they're slightly different. Which one is used for the gas, and which one is used for the beer, and how can I tell the difference?

3 Answers 3


Hmmm...Not an easy question to answer, since there are three types of ball-lock posts.

The gas posts all have what I would call a "double-nut" look. The base of the post, the part where you put your wrench to take them off, have a line around it, making it look almost like it's two parts.

THIS has pictures. Look at the gas posts, on the bottom part, from the side. The place where you would put your wrench. (looks like the head of a nut or bolt) You will see what I mean.

In addition, some older Firestone Champions will use a 12-point bolt arrangement on the gas line rather than the normal six point. Those are pretty rare, however.

Hope that helps.


Its a very subtle difference and hard to see. If you look at the post from the side and then scan down the post you will see these features: Top of the post, the O-ring, straight shaft, then the first flange, an indentation and another a larger flange, more shaft, then the nut. That very first flange is where the primary difference is. That first flange of a gas post is slightly thinner and not as wide as the liquid flange. You almost need to hold two side by side to see the difference.

I recommend getting some enamel paint and putting a dot on the top of the nut of each gas post. I have several kegs that I clean all at once sometimes, and this allows me to toss all the posts in a bucket of cleanser and then quickly sort then out afterwards. Some of my gas posts have nuts with multiple points, so those are easy. But most of mine look very similar to the beverage posts.


All of my kegs have the liquid side labeled "Out" in raised plastic near the base of the post.

Other than that, if you really have to force it, you've probably got it on the wrong one.

  • 1
    The OP is talking about telling the posts apart if you've taken them off the keg to clean them.
    – brewchez
    Mar 22, 2011 at 14:19

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