Keezer Temp probe location

I previously placed my probe in a beer glass with water on the hump. I found my freezer cycling more often that it should seeing as it was about 35 degrees through out the month. I installed a fan and that didn't affect the temp probe, but it helped maintain even temperatures. I switch to a regular plastic water bottle that had been roasting in my car and figured i wasn't going to drink it. I also put it up on a wood block so that it didn't have direct contact with the hump/freezer wall (insulated the hole i punched).
That seemed to fix my problem. But strolling around the neighborhood with my dog, I found one of those SS water bottles and wondered if that would be better since it would mimic the steel of the kegs. I wonder about the thin walls of the bottle, so should I stay with my plastic one?

I would just let it dangle without being in contact with anything.

When the probe is in liquid the temperature transfer of the liquid is delayed (well insulated) so the fridge/freezer will run until the liquid changes temp which by that time the ambient temp is far below your desired temp and will continue to drop even further. Then when the water triggers the controller to turn on again, the ambient temp is much higher than wanted. This creates large swings in ambient temperature your beer is exposed to which quickly degrades the quality of the beer.

When the probe dangles unaffected by any other elements the temperature that the beer is exposed to is much much more steady and desirable to the yeasties.

+1 to the dangle.

In all reality, you don't really need to have your temp controller spot on. Where it matters is inside the keg. Take a temp of your beer after you pour it. Then use that to zero in on the temp you want. Doesn't matter where the probe is as long as you are consistent.

I have a cheaper controller for my fridge with the manual dial and I don't really pay attention to it. My fermenter on the on the hand.... that's a whole different ball game.

I'm a dangler. I admit it. My probe sits about 8" off the floor of the freezer and rests against the edge of one of the kegs.

My freezer cycles 3-5 times a day on average and never runs for more than 5-10 minutes. I tried the water bottle method and it cycled about as often but the temp fluctuated more.

In reality, 5 gallons of beer is enough thermal mass that it wont change much, especially in a well insulated freezer.

A lot of people install fans to move air around to even out temps, but I've never bothered. My freezer is dry and the beer is always cold.

My probe is insulated on keg side, but I don't think it is big difference since when beer gets cold it will stay in few degrees no matter where you measure temperature.

I am not trying to highjack this thread, but I have a related question. How do you out your probe in the keezer? I am about to acquire a chest freezer that I will use to store kegs. Currently, I have small refrigerator that I just drilled a hole in the side of and placed the probe through and then just caulked up the hole (lagering fridge). I was wondering if I would hit any cooling lines with the same approach with the chest freezer. I have also considered just hanging the probe through the chest door so that the door just closes on it, but Ivan worried this might damage the temperature controller over time from people each time they open and close the chest to get the picnic tap to get a beer (I don't think guests will be very careful with the temp controller). Thoughts?

nolabrew85 said:

I am not trying to highjack this thread, but I have a related question. How do you out your probe in the keezer? I am about to acquire a chest freezer that I will use to store kegs. Currently, I have small refrigerator that I just drilled a hole in the side of and placed the probe through and then just caulked up the hole (lagering fridge). I was wondering if I would hit any cooling lines with the same approach with the chest freezer. I have also considered just hanging the probe through the chest door so that the door just closes on it, but Ivan worried this might damage the temperature controller over time from people each time they open and close the chest to get the picnic tap to get a beer (I don't think guests will be very careful with the temp controller). Thoughts?

Click to expand...

I use this method with a ranco. No damage. Just don't let careless people touch your equipment.

nolabrew85 said:

I am not trying to highjack this thread, but I have a related question. How do you out your probe in the keezer? I am about to acquire a chest freezer that I will use to store kegs. Currently, I have small refrigerator that I just drilled a hole in the side of and placed the probe through and then just caulked up the hole (lagering fridge). I was wondering if I would hit any cooling lines with the same approach with the chest freezer. I have also considered just hanging the probe through the chest door so that the door just closes on it, but Ivan worried this might damage the temperature controller over time from people each time they open and close the chest to get the picnic tap to get a beer (I don't think guests will be very careful with the temp controller). Thoughts?

Click to expand...

For both my probes, Johnson controller and a Ranco, I have nothing special, I just open the chest door, drop it in and close the door. It is loose enough so there is no pinching on the Johnson, the Ranco has a pretty durable probe.

Eventually, when I got unlazy and finish the collar to my chest freezer I'm going to drill a hole in the collar to drop in through.

i have my probe (STC-1000) in a white labs vial filled with sanitizer solution and resting on top of my co2 tank. It helped me from cycling on/off too much like it did when I had it just hanging in free air.

Brewing_Master said:

I would just let it dangle without being in contact with anything.

When the probe is in liquid the temperature transfer of the liquid is delayed (well insulated) so the fridge/freezer will run until the liquid changes temp which by that time the ambient temp is far below your desired temp and will continue to drop even further. Then when the water triggers the controller to turn on again, the ambient temp is much higher than wanted. This creates large swings in ambient temperature your beer is exposed to which quickly degrades the quality of the beer.

When the probe dangles unaffected by any other elements the temperature that the beer is exposed to is much much more steady and desirable to the yeasties.

Click to expand...

Dangling can be dangerous for the compressor, especially if your controller doesn't have a compressor delay setting, or if you open the freezer a lot, or if there will be periods where it's relatively empty. There have been a few people here that have killed brand new freezers by dangling the probe in a freezer with very little thermal mass in it.

The thermal mass of a small water bottle is so much less than that of a keg, that the temp swings of the kegs are always going to be significantly smaller than the temp swings inside the bottle. Yes the ambient temps will overshoot, but that's actually a good thing, and it won't have any appreciable impact on the beer temp. Larger ambient swings aren't going to do anything to damage the beer in a keg, as long as the beer temp remains constant.

And the OP is asking about a keezer, so I'm not sure how that applies to keeping yeasties happy. If you want to keep the yeasties happy during fermentation, you need to keep the beer temp as close to constant as possible. Since active fermentation is highly exothermic, dangling the probe isn't very effective at doing that at all. It will result in a beer temp significantly warmer than the controllers set point during active fermentation, and equal to the set point afterwards. Taping the probe to the fermenter and covering it with some insulation will keep the beer as close to constant as possible while also minimizing the risk of short cycling the compressor.

FWIW I have my keezer probe taped to the outside of a small water bottle that sits on the hump.

i am a dangler, though i have my probed wrapped in bubblewrap just so it isn't resting on the wall of the keezer where it may get a slightly cooler reading if it is on.. if your controller has a delay you are good to go.. i can't imagine anybody opening their keezer often except for when changing kegs, so i would recommend the bubble wrap method..