chest freezer for fermentation

[GR22]

OK, this is just my 2nd batch: I brewed the Thunderstruck Pumpkin Ale (extract) yesterday, also made a yeast starter. First time using a chest freezer I set up with temp control. Freezer temp is holding well at 67 F, but a temp probe I taped to the fermenter (with bubble wrap) is reading 72 - 73. Fermentation is aggressively going (with a blow tube). Reading old posts, I'm now wondering if I should have taped the temp probe from the temp controller to the fermenter (plastic bucket)?

 

[passedpawn]

OK, this is just my 2nd batch: I brewed the Thunderstruck Pumpkin Ale (extract) yesterday, also made a yeast starter. First time using a chest freezer I set up with temp control. Freezer temp is holding well at 67 F, but a temp probe I taped to the fermenter (with bubble wrap) is reading 72 - 73. Fermentation is aggressively going (with a blow tube). Reading old posts, I'm now wondering if I should have taped the temp probe from the temp controller to the fermenter (plastic bucket)?

Yes, you should tape the temp control sensor to the fermentor. In fact, it's best to tape a rag or other insulator over the sensor, thus insulating the sensor from the ambient temp in the freezer.

 

[GR22]

Actually, that makes sense. I switched the temp probes (bubble wrap protects the probe on the fermentor. I'm curious to see how cold the freezer has to go to get the fermentor to 67.

 

[GR22]

If anyone's curious, the system seems stable with the fermentor holding at 67 F while the freezer internal temp is in the low 40's. This is with rigorous (judging by blow tube activity) fermentation about 20 hours from pitching the yeast starter.

 

[djfriesen]

That seems like a really drastic temperature difference. I would not have expected that. But whatever you have to do to keep that fermentation temp where you want it.

 

[PT Ray]

That seems like a really drastic temperature difference.

Just what I thought.

Where is the t-stat probe for the freezer? It sounds like its position is causing an inaccurate reading. I've got three chest freezers that I've pulled the original t-stats and placed the new probes in the same location. The t-stat reading is pretty consistent with the fermenter.

 

[passedpawn]

That seems like a really drastic temperature difference. I would not have expected that. But whatever you have to do to keep that fermentation temp where you want it.

That difference won't "stick". His freezer overshot. It will go up, down, and settle at a few degrees cooler than the carboy.

 

[C-Rider]

Just bought and plugged in my 7.1 cuft freezer from Costco. $130 w/tax
Attached the temp controller and waiting for it to settle down to say 64*. Will then take one fermenter bucket that in now in a fridg and move it to the freezer. That frees up the fridg to condition in.

Next to the freezer is my collection of cleaned bottles waiting to be filled. All this is under the house.

 

[GR22]

I'm using a temperature controller, not the thermostat for the freezer. The temp probe for the controller is on the outside of the fermentor\plastic bucket with bubble wrap protecting it from the actual air temp inside the freezer. I have another temp probe not associated with the controller just hanging inside the freezer (not touching any walls) just to see what the internal air temp is. I suspect the large temp difference is due to active fermentation? I bet the difference is reduced in a few days, but this is the first time I'm using the chest freezer so we'll see.

 

[GR22]

For what it's worth, today the temp inside the freezer is within a few degrees of the temp of the fermentor. I guess either it took overnight to equalize and/or vigorous fermentation played a role. The blow tube is still bubbling, but less frequently than yesterday.

 

[HomebrewMTB]

You might consider a carboy thermowell.

http://www.brewershardware.com/16-Stainless-Steel-Thermowell.html

You just need to add a carboy cap or double drilled bung.