Air Gap Forming In Beer Line

[Dilbert]

G'day

About 30 minutes after pouring a beer through my floryte tap, an increasing air gap forms in the beer line at the back of the tap. Overnight this increases to about 500mm or so, and really messes up the first pour. Is it CO2 coming out of solution? Why?

The setup is in a converted chest freezer, controlled at about 3degC.

Dilbert

 

[MarkBastard]

Yes it's probably co2 coming out of solution.

Why does it happen? Several possible reasons including...

* The line is warmer up there, maybe even your tap is attracting the warm outside air and transferring the warmth to the beer / beer line.
* The line is too long.
* A small leak somewhere.

 

[Dilbert]

* A small leak somewhere.

Would beer not leak out rather than air in? The line is pressurised, after all?

Thanks for the other points; it is a fairly new setup so I will double check.

 

[cdbrown]

The temperature difference is the main reason. Warm beer will readily release the gas out of solution.

If the line is too long you would be getting a very slow pour, unless you then increased the gas pressure to overcome at which point the beer could be overcarbed. Is your pressure around 80-90kpa?

The leak could be towards the top of the diptube allowing the gas to move to the highest point and pushing beer to go back into the keg. May be a bad seal between the diptube and the keg.

 

[MarkBastard]

* A small leak somewhere.

Would beer not leak out rather than air in? The line is pressurised, after all?

Thanks for the other points; it is a fairly new setup so I will double check.

I'm not sure to be honest, I just know that this was the reason why it happened to someone here. As mentioned a leak in the dip tube or around there can cause this.

 

[Guest Lurker]

Yes it's probably co2 coming out of solution.

Why does it happen? Several possible reasons including...

* The line is warmer up there, maybe even your tap is attracting the warm outside air and transferring the warmth to the beer / beer line.
* The line is too long.
* A small leak somewhere.

Warmer, yes that is exactly why.

Longer, no, the length of line only makes a difference to the pressure when you are pouring and the beer is moving.

Leak, no, the beer is under pressure, if there was a leak beer would come out, air wouldnt go in.

You will always get bubbles behind your tap and a frothy first pour if it is a bit warmer at the tap. The solutions are to never stop pouring beer, so the beer itself keeps the tap and line cold, or keep the line and tap cold when you are not pouring beer, which could be as complicated as a cooling jacket or as simple as a fan circulating air in the freezer.

 

[MarkBastard]

Longer, no, the length of line only makes a difference to the pressure when you are pouring and the beer is moving.

Leak, no, the beer is under pressure, if there was a leak beer would come out, air wouldnt go in.

1 - I've found beer comes out of solution more easily when line lengths are too long for the given pressure for whatever reason. This is when using picnic taps and clear beer line. Definitely not a warmth issue.

2 - Some leaks can be internal. The thing keeping beer in the beer lines is the head space pressure in the keg pushing down on the beer, which gets pushed out the dip tube. If there's a small leak in the top of your dip tube then naturally some beer can come out and be replaced with co2 (rather use this term than 'air' to be honest).

(Note 1 is from personal experience and 2 is from a thread on this board, neither reply is based on scientific theory or any of the other nonsense people use for replies here. Experience > Theorising).