Fermentation Temperature Delima

[brianccarr]

I have a freezer with a temperature controller in an outside shed. This shed has no AC or heat. During the winter months here in the south, day time high temperatures can get to 80° and nighttime temps can get down into the thirties within a 24 hour period. My issue is that my fermentation freezer can maintain temps just fine during the warmer day. What do you do at night when the nighttime temps go low and in turn lowers the temp of the freezer below where it needs to be. It would be a lot of trouble to switch to a heat wrap at night then take it off every morning and switch to freezer control.

 

[Staylow]

I bought a heating pad from Williams Brewing. One side is adhesive, so I stuck it to a mini fridge door (the one I used for the cooling aspect of my ferm chamber), and stuck it inside. You'll need a temp controller that can switch from cool to heat, such as an STC-1000.

I've had it for about 3 years now and it works great.

 

[DaWhip]

If you can get a controller that does both hot and cold, you'd be set. The inkbirds are less than $40 and work well. If your stuck with what you have, I'd suggest starting by making sure you are staying cool enough. Doubt you'll lose enough heat inside the freezer at night to really hurt anything. Try and keep an eye on it the first few days with the big temp swings and switch if the opposite is true.

 

[SanPancho]

+1 on actually checking the temp at night. Or better, at maybe 4-5am. Next time you wake early to take a leak, check the temp. Might not be a problem at all.

If it is an issue i would advise a small 4" inline fan or computer fan. They generate quite a bit of heat. I have a small chest freezer that will run into the high 70s to 80s if the fan is on but no cooling. Its a little more work for the cooler, but the fan also circulates the air which gives you more even temps and helps cool the fermenters down more quickly.

 

[brianccarr]

I have a Thermo-Star Dual mode temp controller with the 12" probe that goes into a rubber stopper on the fermenter. The fermenter lid has two holes, one for the probe and one for the airlock.
When I initially put the fermentor into the freezer, I had it set to maintain a temp of 64°. The next morning the wort temp had dropped to 46°. We had a 35° night. My freezer is quit large and will hold 6 carboys. I ended up bringing the carboy into the house and maintaining my home thermostat at around 63°. The things we do for beer!

 

[DaWhip]

Dang, that is a pretty good drop. Maybe I need to keep a closer eye on mine...haven't hooked anything up to the heat side of my controller yet.

I like the fan idea above. Filling the freezer will also help. Mine only holds one carboy 5 gal and two 1 gal carboys but I filled a lot of the air space with icepacks and small bottles of water. it keeps the temps a lot steadier with more mass in there.

 

[Gravity]

If you can get a controller that does both hot and cold, you'd be set. The inkbirds are less than $40 and work well. If your stuck with what you have, I'd suggest starting by making sure you are staying cool enough. Doubt you'll lose enough heat inside the freezer at night to really hurt anything. Try and keep an eye on it the first few days with the big temp swings and switch if the opposite is true.

I saw one at home depot that works for both hot and cold temps with the option to also put it on a timer, might be worth your time...50$ i think...

 

[brianccarr]

I saw one at home depot that works for both hot and cold temps with the option to also put it on a timer, might be worth your time...50$ i think...

My controller actually does do both; there is manual switch to go between cooling and heating. Are you saying get an electric heat wrap for nights and then switch back to cooling with the freezer in the days?

Edit: I think I understand. Get a second controller (which I have) just to control a heat wrap. I would need two timers; one for each temp controller. Am I understanding that correctly?

 

[Horseflesh]

What do you do at night when the nighttime temps go low and in turn lowers the temp of the freezer below where it needs to be. It would be a lot of trouble to switch to a heat wrap at night then take it off every morning and switch to freezer control.

Before you buy anything to solve this problem, make sure it IS a problem. Run the unit under those conditions and see what the temperature inside actually is. Freezers are insulated after all. It might ride out the cold nights without getting any colder inside.

 

[brianccarr]

Before you buy anything to solve this problem, make sure it IS a problem. Run the unit under those conditions and see what the temperature inside actually is. Freezers are insulated after all. It might ride out the cold nights without getting any colder inside.

I agree; good advice. I will put a thermometer in the freezer and take some recordings for a few days. I was going by the readout of the wort temperature on my controller so I assumed it was correct.

 

[DaWhip]

My controller actually does do both; there is manual switch to go between cooling and heating. Are you saying get an electric heat wrap for nights and then switch back to cooling with the freezer in the days?

Edit: I think I understand. Get a second controller (which I have) just to control a heat wrap. I would need two timers; one for each temp controller. Am I understanding that correctly?

If you are going to get a second controller, you can go with one like this. This is what I was referring to in my earlier posts. It will do both heat and cool automatically, no switching needed. It will make your current one obsolete, but I'm sure you could find another use for it.

 

[SanPancho]

yes, exactly. cool AND heat, not either/or. otherwise youd have to switch back and forth every day and night.

the fan is still a good idea, but too small for your box to be heat source. and the ol' floodlight in a coffee can is probly not enough heat either.

fermwrap will do the job, but it is expensive though. a good size heating pad is another option. (make sure it doesnt have auto shutoff or it could be useless). with a small fan to circulate air im guessing that should be enough to warm the entire box. last heating pad i bought on amazon was like 10-15 bucks i think. inline fan at hardware store was less than 10. can even use computer fan if you have old one somewhere.

 

[brianccarr]

I didn't know such a controller existed; and at less than half of what I paid for my other. I have several heating pads designed to help grow vegetable seedlings. Seems like dropping one of those in the freezer hooked up to the heating side of the inkbird would maybe work. Looks like there is only one probe on it. So I would loose the ability to measure the actual wort in the fermenter if I'm understanding this correctly.

 

[DaWhip]

I tape the probe on mine to the carboy. Heat side kicks on when it is too cold, cold side kicks on when it is too hot. Not sure if that answers your question but you should be able to run it off of actual wort temp if you are using a thermowell. It has a delay setting to keep your freezer from cycling too often. I would just max that, 10 minutes I think, because it might take some time for the wort temp and ambient temp to equalize. That should keep the hot and cold from cycling back and forth too much.

I use a seedling heating mat as well and it works great, but my freezer is significantly smaller than yours, but it will probably work. Mine only kicks on for a couple minutes and it is enough.

 

[brianccarr]

That's awesome. I will order one today. Might use a splitter off the heat side and use two heating pads since the freezer is large.

 

[harrke]

I use an inkbird controller with the probe in a thermowell. Cold plug to the refrigerator and heating supplied by a very small (desktop) ceramic heater. This works really well.

 

[brianccarr]

Before you buy anything to solve this problem, make sure it IS a problem. Run the unit under those conditions and see what the temperature inside actually is. Freezers are insulated after all. It might ride out the cold nights without getting any colder inside.

Last night I had an 11° drop inside the freezer. I am a little surprised it would fall that much.