Temperature difference in freezer fermentation chamber

[Mike@M]

I’m building a fermentation chamber using a freezer and Inkbird controller. I was wondering if anyone had noticed any temperature differences between the carboy sitting in the bottom of the freezer vs the one sitting on the compressor hump?

 

[IslandLizard]

Cold air sinks, and freezer lids are notoriously poorly insulated. So the higher placed the warmer, the lower the colder.

Do you have the probe against a carboy with a piece of insulation foam over it?
Compressor delay set to max (10 minutes IIRC).
Calibrated the probe?

 

[Mike@M]

Cold air sinks, and freezer lids are notoriously poorly insulated. So the higher placed the warmer, the lower the colder.

Do you have the probe against a carboy with a piece of insulation foam over it?
Compressor delay set to max (10 minutes IIRC).
Calibrated the probe?

Haven’t got it set up yet,just got the collar attached yesterday. That’s the way I’m planning on doing it though.
I’m thinking of making some sort of platform so both carboys will be at the same height.

 

[Gnomebrewer]

My keezer freezes beer at one end (non compressor end) when the other end (compressor end) is at 4C without a fan to recirculate air. As IslandLizard said, measure the temperature of your fermenting beer rather than air temp as there will be variation within the freezer. At the very least, stick a fan in there.

 

[IslandLizard]

My keezer freezes beer at one end (non compressor end) when the other end (compressor end) is at 4C without a fan to recirculate air.

You just brought up another good point. There are no coils in the hump, so that area remains warmer, without air recirculation. The hump is probably not as well insulated as the outside mantle, either, with a hot compressor sitting underneath. Explains why the other end freezes your beer, it's surrounded by 3 sides of coils.

 

[IslandLizard]

I’m thinking of making some sort of platform so both carboys will be at the same height.

You could, but the shelf needs to be fairly open for natural air recirculation. A solid piece of plywood would prevent flow.
Much better yet, use a recirculation fan. A spare computer fan should work fine.

Are these large glass carboys? If so, be very careful handling them!

 

[Mike@M]

You could, but the shelf needs to be fairly open for natural air recirculation. A solid piece of plywood would prevent flow.
Much better yet, use a recirculation fan. A spare computer fan should work fine.

Are these large glass carboys? If so, be very careful handling them!

They are the 6 gal better bottles. I thinking about a open slat design for the shelf and then put a computer fan under it. Getting bottles at the same level should help with lifting them out.

 

[IslandLizard]

They are the 6 gal better bottles. I thinking about a open slat design for the shelf and then put a computer fan under it. Getting bottles at the same level should help with lifting them out.

Ah, those are not as fragile, but still very slippery.
Maybe use Brewhaulers, or something like that. Leave them on while in the ferm chamber.

Wire clothing shelves may work. They're very permeable. If needed, put a similar (wire) support in the center.

But... is your freezer deep enough to accommodate them on a shelf that high up without having to build a collar?

 

[beernutz]

They are the 6 gal better bottles. I thinking about a open slat design for the shelf and then put a computer fan under it. Getting bottles at the same level should help with lifting them out.

 

[Mike@M]

But... is your freezer deep enough to accommodate them on a shelf that high up without having to build a collar?

I added a 6 inch collar because it would only hold one Better bottle without one.

 

[Mike@M]

One of those should work upside down as a shelf.

 

[beernutz]

One of those should work upside down as a shelf.

They will however I had to cut one in half to serve as a shelf in my freezer even with an added collar. It wasn't hard to do with a hand saw and would be piece o cake with a power saw.

 

[Gnomebrewer]

They will however I had to cut one in half to serve as a shelf in my freezer even with an added collar. It wasn't hard to do with a hand saw and would be piece o cake with a power saw.

If anyone does this with a power saw, please wear a full face mask and other protective clothing - plastic missiles can do some serious damage.

 

[Mike@M]

If anyone does this with a power saw, please wear a full face mask and other protective clothing - plastic missiles can do some serious damage.

Did mine today with one of the multi-tools worked great.