Chest freezer temp variance

[#brewlife]

So I’ve just moved to using a chest freezer as fermentation chamber.
Got the first batch in there with temp control set to 20 with a .5 differential. Problem I see is the compressor kicks in at 20.5 but then the temp goes down to 16 ish before it starts warming back up.
Is this too much? Will the beer yeast work if the freezer is dropping temp that much?
Option I see is a heat belt to keep it on a tighter leash.
Any advice, suggestions?
Cheers

 

[Maheel]

whats your probe sitting in?

I run a keezer and probe is in a bottle of water and goes up and down but air temp goes lower.

air temp kind of has to, to start shifting temps down

i would not heat belt it.. you will work the freezer harder

 

[#brewlife]

whats your probe sitting in?

I run a keezer and probe is in a bottle of water and goes up and down but air temp goes lower.

air temp kind of has to, to start shifting temps down

i would not heat belt it.. you will work the freezer harder

It’s just taped to the side of the fermenter with a sponger over it.
The bottle of water is not a bad idea, though the mass of it will likely be a lot smaller than the fermenter which means it will cool faster and stay cool longer?

 

[Maheel]

others will chime in with valuable opinion

i reckon your 16 is fine.

if you had the probe at the middle of the ferment the air temp would get very cold before the ferment gets to 20 but once there the FVT should have less variance but the air temps still would have a large variance.

i just run air temp in my ferment fridge and have no idea where the ferment temp actually is in my pressure fermenter. Beer is good but

 

[koshari]

What you are seeing is overshoot.

As maheel pointed out in the previous post there has to be a relativly large change in the air temp before the liquid in the fermenter catches up, by this time the air temp as way over the set point, then the controller will drive the process the other way, imo you would be best letting the controller control the ambiant air temp and that will then have the liquid follow. so try uncoupling the sensor from the fermenter and just let it sit in the air space away from the influance of the keezers wall. In mine i have a patch of styrene glued to the wall about half the depth of the cabinet and then have the sensor stuch to the center of the styrene patch.

 

[brewermp]

Koshari is right on overshoot. I had the same problem as you.

I have a chest freezer as a FC and I dial the freezer (you should have an adjustment dial somewhere) dependant on what stage I am fermenting at.

So when it is a normal ferment I turn the temp of the freezer up so it doesn’t freeze hard. Then when I cold crash I turn it down

 

[#brewlife]

Koshari is right on overshoot. I had the same problem as you.

I have a chest freezer as a FC and I dial the freezer (you should have an adjustment dial somewhere) dependant on what stage I am fermenting at.

So when it is a normal ferment I turn the temp of the freezer up so it doesn’t freeze hard. Then when I cold crash I turn it down

I did crank the freezer back before I went to bed last night so I’ll monitor to see the drop. Where do you locate the probe?

 

[brewermp]

Mine is attached to the side of the FV with a stubby cooler as insulation.

 

[#brewlife]

Thanks mate. The freezer setting was too high. Wound it right back and it’s stitting between 20.3 and 19.7.
Just hope it gets started.
Called in sick to look after my beer. Lol

 

[brewermp]

Thanks mate. The freezer setting was too high. Wound it right back and it’s stitting between 20.3 and 19.7.
Just hope it gets started.
Called in sick to look after my beer. Lol

That would be my priority haha. After all a mans gotta drink..