Gas Bubbles in Keg Lines

[StickSalute]

Hey everyone. First post here. I'm sure this has been discussed, but I couldn't find a satisfactory answer. It seems to me that most people who have trouble with CO2 coming out of solution in their lines have something like a tower setup or something similar, or they have cleaning issues. I've been as thorough as I can with cleaning and have seen no change, so I'm as confident as I can be on that.

My setup is a small chest freezer (you could fit 4 corny kegs in there if you really wanted to, but I only have 2) with a wooden collar that I built to run the lines and taps through. I have a temperature controller on it which is currently set to 36 F (I'm lagering some things in there at the moment, but I see the same problems at warmer temperatures). I installed a small computer fan and wired it to the controller along with the freezer itself to try to circulate the air better. I put a couple small glasses of water in there overnight, one near the bottom and one near the top, and I got something like a 6-8 F difference. It seems to me that the problem is likely caused by the beer in the lines (which obviously come out of the kegs near the top of the freezer) getting warmer than the bulk of the beer in the kegs, causing the gas to come out of solution. I notice I only have a problem if it is left to sit for a while in between pours, although it really only needs like 30 minutes or an hour to cause issues.

Does anyone have any further suggestions to help fix this? Do you think insulation on the lines would work? Should I focus on insulating the collar and the edges of that better? I know the computer fan doesn't deliver a lot of air, but I figured it would be enough in a relatively small enclosed space. Is there a particular way that you would recommend laying out the lines in the freezer to help? I've tried both letting them sag to the bottom and keeping them up higher with no real difference either way.

Thanks for the help.

 

[grv]

Are you serving at a pressure that is lower than the one you carbed at? That's the other situation I've encountered where this happens. I have pretty much the same setup you describe, but I insulated the wooden collar with rigid foam insulation. My lines are coiled in the top, with the computer fan angled to blow air from the bottom to the top of the freezer. If I let things set for a long time (several days), I may see a few bubbles in the lines, but nothing out of control...

 

[day_trippr]

If you're switching the computer fan on and off with the compressor, that's the first thing to change: have it run all the time.

I also coil my 12' 3/16"ID lines on top of my kegs...

Cheers!

 

[k1ngl1ves]

Make sure you have a proper seal around your collar. Warm air seeping into the top will cause lots of issues. It's not really necessary to insulate the collar if it's 2" thick wood. It won't hurt, though it's much more important that it has an airtight seal.


Also, what day trippr said too.

 

[StickSalute]

Thanks for the replies. Those are some great ideas to try.

I didn't really like the idea of running a fan constantly, but I agree that having it only on during the cooling cycle isn't ideal either. Just seemed wasteful to have it going all the time. Do you think it's necessary to have the fan setup to blow the cold air up from the bottom? I mounted mine to the collar at the top (just seemed like the easiest way to do it) and I figured that in that small of a space, any air circulation would do the trick.

I believe I used some weather stripping (or something similar to that) for insulation between the collar and the freezer and then just relied on the existing stripping to insulate between the lid and the collar. And yeah, I didn't put any insulation on the wood because I figured a couple inches of wood should provide enough on its own. Maybe that's the first thing I should look at, though. I'll try to beef up my insulation all over there, I think.

Also, as far as pressure goes, I change the way I carbonate depending on situation, but it doesn't seem to make a difference. There's been times where I carb and serve at the same pressure, so that should be no issue then. Other times I run the pressure up to something like 30 psi for a few days and then drop it down to serve. I know it could be an issue there, but it doesn't seem to be the problem from what I can tell. I usually try to drop the pressure before it's at the level I want and let it finish carbing at the intended pressure.

Thanks again.

 

[day_trippr]

When a freezer compressor shuts off the expansion loop still "makes cold" for long enough that there's usually a pretty decent over-shoot. If you don't keep the air in motion (and it doesn't take much) you end up with a cold zone at the bottom - from where you draw beer - and a warm layer developing on top - where you have many feet of beer line dutifully coiled atop your kegs. Perfect setup for bubbles in the lines and first-pour problems.

Again, it doesn't take much to defeat stratification. The typical 12vdc 80mm "computer fan" running on a 5vdc cell phone charger is usually plenty. And placement usually isn't critical, if you can just rustle a feather anywhere in the cabinet you're good to go. The important thing is not to restrict the fan input or output (no face mounting a fan directly to a keezer lid liner "to blow down" and then wondering why it wasn't doing much - like I saw here a few weeks ago )

If you need some overkill to make the above seem "normal", I use a 120mm 12vdc fan running about half speed to stir my 13cf keezer, a 40mm 12vdc fan running about full speed to pump cold air up the column into my 6 faucet t-type tower, and an 80mm 12vdc fan running about half speed pushing air into an Eva-Dry e-500 mini dehumidifier.

That ought to do it...

Cheers!

 

[StickSalute]

When a freezer compressor shuts off the expansion loop still "makes cold" for long enough that there's usually a pretty decent over-shoot. If you don't keep the air in motion (and it doesn't take much) you end up with a cold zone at the bottom - from where you draw beer - and a warm layer developing on top - where you have many feet of beer line dutifully coiled atop your kegs. Perfect setup for bubbles in the lines and first-pour problems.

Again, it doesn't take much to defeat stratification. The typical 12vdc 80mm "computer fan" running on a 5vdc cell phone charger is usually plenty. And placement usually isn't critical, if you can just rustle a feather anywhere in the cabinet you're good to go. The important thing is not to restrict the fan input or output (no face mounting a fan directly to a keezer lid liner "to blow down" and then wondering why it wasn't doing much - like I saw here a few weeks ago )

If you need some overkill to make the above seem "normal", I use a 120mm 12vdc fan running about half speed to stir my 13cf keezer, a 40mm 12vdc fan running about full speed to pump cold air up the column into my 6 faucet t-type tower, and an 80mm 12vdc fan running about half speed pushing air into an Eva-Dry e-500 mini dehumidifier.

That ought to do it...

Cheers!

Thanks for the follow-up. So I've just got an 80mm 12vdc fan on something like 1/2" standoffs mounted on the wooden collar. It's running on a 12vdc power adapter cause that's what I had, so it is at full speed. You think that should be good then? And it's probably not necessary to worry about tilting it downwards or anything like that?

I probably will get some better insulation for the collar. I'm thinking of getting some styrofoam that I can cut to size and line the collar with. There's ~1/4-1/2" of the freezer wall extending inside the collar, so I'm thinking that I will cut the styrofoam so that it hugs the collar and then extends down over part of the freezer wall to help insulate the collar/freezer gap, along with the weather stripping insulation that is already there. Hopefully that will do the trick.

Again, thanks for the help.