Air In Tap Lines

[phil4124]

Gday

Have been lurking around the threads gaining some valuable info, but have failed to find any info on a problem I have come accross with my setup.

I have recently stepped up to kegging and have been setting up my system. I believe I have a balanced system and have been successfully pouring many a decent glass BUT I am finding that I always getting a buildup of air/gas in my line at my tap. This results in an initial blast from my tap everytime I pour the next beer!! I have just installed a full stainless gun which is now in the fridge (ie cold) but am still getting this gas buildup..... :huh:

I am using clear silicon 5mm hose and my pouring pressure is around 5-6 psi. Length is around 1.2 mtrs.

Is this normal? Anyone else had a similar problem? I would appreciate any help

Thanks

Phil

 

[cdbrown]

From what I've read about similar issues is that the seals on the keg may be leaking or some small holes in the liquid dip tube. In a normal situation once the beer fills the line it remains under pressure and stays in there, if gas/foam is forming that means the CO2 is coming out of solution in the beer line and pushing the beer back into the keg (could this means it's carbed higher than the pouring pressure??). Or CO2 is getting past the seals and entering the line pushing the beer back down.

Hopefully someone with more knowledge will come along and either shoot my theory down or confirm it.

 

[paul]

Your system isnt balanced.

For beer to be carbonated it needs to be stored with about 12 psi on it.

Up the pressure to about 12 psi and double the line length.

Because your beer is at 5 psi the gas comes out of solution and builds up behind the tap.

 

[cdbrown]

According to crozdogs spreadsheet Phil needs about 1.8-2m of beer line (depends on how high above the centre of the keg you are pouring) and 11.9psi based on serving temp of 4 degC, 2.5 vol CO2. If you go colder say 2degC then only need 10psi and 1.5m length.

 

[phil4124]

Your system isnt balanced.

For beer to be carbonated it needs to be stored with about 12 psi on it.

Up the pressure to about 12 psi and double the line length.

Because your beer is at 5 psi the gas comes out of solution and builds up behind the tap.

Paul, that does make sense and it was the thing I found was unusual. It does appear the Co2 is coming out of the beer.
I did think though that the length of line I was using was correct when I used the calculations for balancing including the height above the keg I am using. But obviously something is not right.

I think I will start with up-ing the pressure and slightly longer line. Probably the easiest and cheapest place to start.

It is so nice to have some input...............thanks guys

P.S. And wouldn't you know, 12 psi has stopped the bubbles forming in the lines. Just though I would test the theory with another glass............. Longer lines will slow the pour, I guess..?..

 

[cdbrown]

Yes - longer lines and/or higher tap position will slow the pour rate.

 

[Zwickel]

the solved gas in a liqid depends on the pressure and temp.
As soon as one of that parameter varies, gas gets in or out the liquid.

In a fridge the temp from bottom to the top can have a difference of about 3 to 4 C.
So if the beer comes out from the bottom of the keg (diptube reaches to the bottom) into the tube at top of the fridge, gas will be released into the tube.

You can avoid that by installing a fan that provides a homogenous temp within the whole fridge.

Cheers

 

[Beer Guy]

Here is a link that may help in general as a basic trouble shooting guide

http://www.kegless.com/index.php?main_page...amp;pages_id=26

Beer lines are a black art and if memory serves a very large multi national spent a few million dollars inventing something like this

http://www.patentstorm.us/patents/4720076-description.html to help reduce that build up of gas.

As pointed out you can not prevent this build of gas first beer later you can reduce it by ensuring lines are insulated or cold from keg. if you let the beer in the line sit stationary for ten or fifteen minutes that first bit of beer will fob it happens in your local pubs beer line system so it follows it should happen in your home system.

 

[alexbrand]

Well, since I've installed a small fan into my dispensing fridge I have no more bubbles in the beer lines and also after a longer period without pouring there's almost no froth coming out of the tap... As Zwickel mentioned before: a fan really helps.


Alex

 

[phil4124]

Top of the shopping list is some longer lines. 12 psi keeps the bubbles out, but the pouring pressure is too great.

I have a newly aquired chest freezer with a Mashmaster digital temp controller coming, and I have a spare CPU fan floating around.............. Sounds like it wouldn't be a bad idea.

Thanks for all the input to all. :icon_cheers:

 

[SJW]

Mke sure u have the correct poppets in the posts. I had trouble with a Firestone keg with Cornie poppets. It caused the beer to foam like mad.