Keezer temp control

[helterscelter]

Recently I built a collar keezer. My set up for 10 corny kegs And has 4 intertap faucets.

I've been trying to carb up a cream ale for several weeks with no luck.

I keep the keezer set to 38f +-2f. I've got my temp probe hot glued into a 20oz Coke bottle full of water. I set the bottle square in the middle of the keezer on the floor. I've got a fan circulating, pulling air from the bottom and pushing it across the top of the kegs.

8 of my kegs are set at 15psi and seem ok. The two cream ale kegs I had at 15psi for 2 weeks and have progressively increased the psi to 28psi and held it there for 3 days. I would expect it to be way over carbed but unfortunately it seems very flat. Maybe 1vol co2.

I started thinking about what could cause this. So I checked the temp if the beer coming out of the tap. 55f. That's 15f higher than my temp controller is telling me it should be.

So what can I do?

The two on the hump are the ones I'm having trouble with. But all of them seem to be pouring at 50f+ (tho the others are seemingly carbed up ok)

 

[day_trippr]

Wow, that's tight AF. Nice job packing all that in there!
Where did you locate the controller's probe? If it's just dangling in free air that would explain why the kegs aren't colder...

Cheers!

 

[Pkrd]

I like your setup. Needs more taps though.

You'll still get around 2 volumes at 55F 15PSI.

Are you giving it a good pour before you do a temperature check?
Do the lines on those kegs sit on top of the kegs right under the lid?

 

[doug293cz]

Wow, that's tight AF. Nice job packing all that in there!
Where did you locate the controller's probe? If it's just dangling in free air that would explain why the kegs aren't colder...

Cheers!

Actually, dangling in free air works quite well in a keezer. There is no heat generation (as with fermentation), so if the average temp of the air is in range, so will be the kegs, If there is good air circulation in the keezer. Putting the temp probe in a damper (the container full of water) does nothing to improve the temp control within the keezer. Tight packing in the keezer is the most likely problem. You need to have good air circulation in order to get a uniform temp throughout the entire cooled volume. Fans can help a lot, but if air can't circulate, then the fans are a waste.

Brew on

 

[day_trippr]

My own experience indicates the best way to get your beer at a desired temperature in a keezer without flogging the compressor is to have the controller control the beer temperature, not the air temperature.

This plot shows the cabinet air temperature at the top and bottom of my 13cf/6 keg keezer as well as the beer temperature in one of the 6 kegs, over the last 24 hours. The controller is set for 35°F +/- 1°F, and there is a 120mm fan keeping the air well stirred as evidenced by the two air sensors. Note the compressor cycled four times in 24 hours and ran for 1 hour +/- 10 minutes per cycle for a duty cycle under 20%.

Note the very smooth slope of the beer temperature reading versus the two cabinet air sensors. Otoh, note where - ie: how quickly - the air temperatures cross the set point after a change in the compressor state. Now, imagine controlling the compressor using the air temperature readings and what the cycling would look like (hint: it'd be hella busy).

To me this is a no-brainer...

Cheers!

 

[day_trippr]

Also, if all of the kegs in a keezer are the same temperature the problem probably isn't due to lack of airflow..

Cheers!

 

[helterscelter]

It's hard to see but the temp probe is right in the middle cavity of the 8 kegs on floor. I put the probe in a 20oz Coke bottle full of water to help damp the airtemp swings.

I am giving a good pour to clear out the lines when checking the temp and when checking the carbonation. This also cools the taps which tend to stay pretty warm and causes a bit of foaming until they get cold. I probably should get longer shanks to help with that, but I also don't want to increase the heat intake via the taps.. it's not enough foaming to matter much to me when hooked to the kegs on the keezer floor.

The lines do sit Right on top of the kegs under the lid. I probably have 12 inches of dead space above the kegs on the floor and probably 4inches for the two of the hump.

The kegs on the floor seem to be the same temp with the ones on the hump being a bit warmer. I chalk that difference up to the height difference and the fact that my collar isn't insulated. So the head space is possibly warmer, however all the kegs are basically touching the side walls with the kegs in the corners touching in two sides.

As mentioned at 30psi and 55f I should still be getting over 3 volumes. But I'm definitely not anywhere close to that.

I can change up my fans some to help keep the air circulation More homogenous, but not convinced that will make a huge difference

 

[day_trippr]

What the fans will definitely help with is keeping the lines at the same temperature as the kegs, which in turn will cut down on "first pour issues".

fwiw, what I suspect is happening is the compressor isn't running anywhere near long enough per cycle to actually start dropping the keg temperature towards your desired set point. It's crazy that there's such a huge differential between your 38°F set point and the actual beer temperature. That would indicate the probe bottle isn't helping, at least not where it's currently located...

Cheers!

 

[helterscelter]

What the fans will definitely help with is keeping the lines at the same temperature as the kegs, which in turn will cut down on "first pour issues".

fwiw, what I suspect is happening is the compressor isn't running anywhere near long enough per cycle to actually start dropping the keg temperature towards your desired set point. It's crazy that there's such a huge differential between your 38°F set point and the actual beer temperature. That would indicate the probe bottle isn't helping, at least not where it's currently located...

Cheers!

Interesting thought. Might try the good old tape the probe with insulation to the keg trick.

Unfortunately I'm not trying to fix first pour issues so much as trying to figure out why my cream ale isn't carbing. Tho the first pour and temps are definitely concerning.

 

[day_trippr]

Carbonation is so dependent on temperature, and you have to face the reality that eventually you need to get the temperature thing rationalized or drink warm-ish beer forever I wouldn't want to have to manage what's going on - I wouldn't even know where to set my CO2 pressures.
I'd try to fix the obvious issues first and see if anything falls out.

As for the cream ale, I once had a keg of a light wheat beer that refused to fully carbonate - the twin to another keg from the same batch that had no problem reaching an effervescent carbonation level. I eventually discovered the slow-to-go keg had a tiny lid gasket leak, and lacking anything else to go on I attributed the problem to that...

Cheers!

 

[helterscelter]

Carbonation is so dependent on temperature, and you have to face the reality that eventually you need to get the temperature thing rationalized or drink warm-ish beer forever I wouldn't want to have to manage what's going on - I wouldn't even know where to set my CO2 pressures.
I'd try to fix the obvious issues first and see if anything falls out.

As for the cream ale, I once had a keg of a light wheat beer that refused to fully carbonate - the twin to another keg from the same batch that had no problem reaching an effervescent carbonation level. I eventually discovered the slow-to-go keg had a tiny lid gasket leak, and lacking anything else to go on I attributed the problem to that...

Cheers!

Good thought process. Definitely need to get temps stabilized and at the chill I want.

Thanks for all your help!

 

[helterscelter]

Good thought process. Definitely need to get temps stabilized and at the chill I want.

Thanks for all your help!

I may rename this thread to "A tale of two kegs"

Moving the temp probe to be taped to the side of a keg definitely made a difference in pour temperature. Huge improvement.

Carbonation on the keg I have tapped however didn't improve. I kept the psi at 30psi for two full days after the temp dropped. Colder. But still basically flat. Maybe a little more carbonation. But not what I wanted.

On a whim I changed the faucet to the second keg of this batch. Excellent carbonation. Pours with a nice fluffy head.

This must mean I have a leak in the first keg somewhere? I think day_trippr mentioned similar behavior.

 

[SanPancho]

im assuming your chest freezer has no fan? it cools by conduction, with the walls getting cold and transfering that to the chamber.

you put the temp probe in a bottle of water sitting right on the cooling surface. great conductivity.

your kegs sit above the cooling surface on their plastic bases. bad conductivity.

your water bottle is at the right temp, due to great cooling. the kegs, not so much. airflow will help, but air is never going to conduct heat like direct contact with metal.

so as you've seen, moving the temp probe helps the problem. you can either measure one keg and hope that averages out the others. or insulate your water bottle from the cooling surface like the kegs are insulated by their rubber bases.

long story short, your carb problem is most likely gas related, not temp. as you've already surmised, you're gonna have to look for leaks. but at least you know which two are the problem lines...

 

[helterscelter]

im assuming your chest freezer has no fan? it cools by conduction, with the walls getting cold and transfering that to the chamber.

you put the temp probe in a bottle of water sitting right on the cooling surface. great conductivity.

your kegs sit above the cooling surface on their plastic bases. bad conductivity.

your water bottle is at the right temp, due to great cooling. the kegs, not so much. airflow will help, but air is never going to conduct heat like direct contact with metal.

so as you've seen, moving the temp probe helps the problem. you can either measure one keg and hope that averages out the others. or insulate your water bottle from the cooling surface like the kegs are insulated by their rubber bases.

long story short, your carb problem is most likely gas related, not temp. as you've already surmised, you're gonna have to look for leaks. but at least you know which two are the problem lines...

I actually did add fans to help circulate. Afaik the cooling coils are in the sides not the bottom of the freezer so shouldn't be much difference in cooling off the bottle vs the kegs. I think the mass of the water in the bottle vs a keg of beer had more to do with the difference imho.

I do think you're right. I have a leak somewhere in that first keg line or the keg it's self

 

[SanPancho]

huh. thats interesting. most freezers that i've dealt with have the cooling all over the place. in any case, the metal surface is still going to transfer heat better than rubber bases. the mass of the bottle will only skew the results for a day or two until all the kegs equalize- assuming you've got good airflow. putting it on a piece of rubber or wood or whatever will still help out. measuring a keg directly will obviously work too.

but i'm a little skeptical of your airflow. that keezer seems jam packed. but if you're getting the temps down towards where you want them then you're doing something right.

you live in a frat house or something? thats a lot of beer. like..... A LOT.

 

[helterscelter]

huh. thats interesting. most freezers that i've dealt with have the cooling all over the place. in any case, the metal surface is still going to transfer heat better than rubber bases. the mass of the bottle will only skew the results for a day or two until all the kegs equalize- assuming you've got good airflow. putting it on a piece of rubber or wood or whatever will still help out. measuring a keg directly will obviously work too.

but i'm a little skeptical of your airflow. that keezer seems jam packed. but if you're getting the temps down towards where you want them then you're doing something right.

you live in a frat house or something? thats a lot of beer. like..... A LOT.

Lol. Nope. Married with a 5yr old. I had a goal this year to brew 120 gallons. It was a good goal. Unfortunately I completely underestimated my consumption rate and available time. I made it to 70 gallons this year. Don't think I'll have time to do another brew before the new year and I've got about as much as I can drink still in the keezer anyway. Only one of those kegs in there is completely empty . Tho I have been working on the rest.

The keezer looks more packed than it is. I can put my hand between each of the kegs in there. In any direction. It is still tight tho.

I may be wr. Wro. Wrrrroooo.... Wrong. (Whew) about the cooling coils. I've never checked the bottom.

I definitely am getting down to the 38f I set the controller to now, so I think the combination of the airflow and moving the temp probe to a keg helped.

Now to find a leak!

 

[day_trippr]

None of the chest freezers I've owned (3) had evaporators in their bottoms. Which makes sense, imo, as such as setup would likely burn the hell out of any food placed on the floor - and those packages would block the bottom from contributing to the overall cabinet temperature. So...

Cheers!