Heating an outdoor fermentation chamber in cold weather

Anyone out there have any experience keeping a fermentation chamber warm when the ambient temperature is extremely cold? I want to move my 7 cu. ft. chest freezer fermentation chamber into my unheated garage, but it occasionally gets down to -25*F in the winter where I live. I'll probably test a few heaters this winter, but if anyone has experience to steer me in the right direction it would be appreciated.

Do you have a dual stage controller on the chest freezer? If so, just wire in a heater!

I have no personal experience with the matter, but there are lots of ways to do this. It can be as simple as an incandescent light bulb, some people put it in a paint can to block the light. Or one of those reptile heaters that fits in a standard light socket. Or an electric blanket, Fermwrap, hair dryer, etc. So many options. If it were me I'd go with something low wattage like the lightbulb or reptile heater for safety reasons. Regardless, a constantly-running PC fan is a good idea (you probably have one in the chest freezer already), as is running the thing on a GFCI outlet.

Thanks for the reply. I did put a dual stage controller on it because it was always my intent to put the fermentation chamber in the garage. I was just wondering if there was anyone else out there who was dealing with the same type of ambient temps and would mind sharing what they use so I don't have to waste a bunch of time testing different heaters.

I like the paint can heater because its so simple and cheap, but I am not sure if it will be able to maintain the temperature when it gets cold outside even with a 120W bulb. If the bulb burned out it would also be a catastrophic event for my carboys, something more reliable would be preferred. The heating strips/blanke sounds good but if they don't get hot enough its a waste of money.

I have contacted the freezer manufacturer to see if they can give me the R-values of the walls and lid. If they can give me that, or even an overall heat transfer resistance I should be able to calculate how big of a heater I need. I think it will probably have to be over 200 watts.

I agree that a fan to constantly circulate and a GFCI in the circuit are absolutely necessary.

Sorry I don't have any personal experience. It sounds like you've got a good start though. Those are some pretty extreme temps... good luck!

I have no personal experience either, but had a couple thoughts.

How about a corny filled with a glycol solution and a heating element inside.
The glycol solution should give you a time and temp buffer.

I'm a little leery of GFCI usage in such a critical situation. I have witnessed many floodings due to GFCI's nuisance tripping. Don't get me wrong, they definitely have their place and have saved countless lives.

In your case, just unplug your chamber before working in/on it.

'da Kid

The10mmKid said:

I have no personal experience either, but had a couple thoughts.

How about a corny filled with a glycol solution and a heating element inside.
The glycol solution should give you a time and temp buffer.

I'm a little leery of GFCI usage in such a critical situation. I have witnessed many floodings due to GFCI's nuisance tripping. Don't get me wrong, they definitely have their place and have saved countless lives.

In your case, just unplug your chamber before working in/on it.

'da Kid

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I missed what was critical about this situation.

Well maybe "critical" is not the correct word, but I'd hate to open the door to a frozen burst fermenter.

Just use common sense . . . . like we had before GFCI's were invented. Don't work on the electric when there's the chance you could get electrocuted.

Open the door or read the temp controller to check on things, but if you have to work on it . . . unplug it. If you want to troubleshoot it and feel more comfortable with a GFCI, use it.

'da Kid

The10mmKid said:

Well maybe "critical" is not the correct word, but I'd hate to open the door to a frozen burst fermenter.

Just use common sense . . . . like we had before GFCI's were invented. Don't work on the electric when there's the chance you could get electrocuted.

Open the door or read the temp controller to check on things, but if you have to work on it . . . unplug it. If you want to troubleshoot it and feel more comfortable with a GFCI, use it.

'da Kid

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I believe code requires all outlets in a garage to be GFCI, I could be wrong though. If I'm right, OP may have no choice (or it become a bit of a PITA to go without GFCI).

Interesting idea with the glycol, I could put a fairly high powered element in there and not have to worry about burning anything. It would be more reliable than a light bulb and the thermal mass is also a big plus.
I don't want to "waste" one of my cornys if I don't have to, so maybe a cheap pressurized spray can would do the trick instead.
As for the GFCI debate, I will test whichever system i end up choosing with a bucket of water for a few weeks just to make sure it doesn't trip my GFCI breaker and destroy my carboys. Thanks for the heads up on that.

Yes, I also believe that the code has required GFCI protection anywhere there are concrete floors. Garages, maybe basements. They are always a good idea if you run the risk of crossing electricity with yourself and moisture.

The glycol would be the safe RV kind . . . . propylene, I think.

'da Kid

P.S. What is a "cheap pressurized spray can"?

Somthing like this. I'm sure I could find a bigger/cheaper one, that is just one of the first I found with google. Should be able to hold about 150 psi in case the heating element ever needs to really crank out the heat.

Ahh, that's what I thought it was. Great for spraying flashless solvent.

Can we revisit the corny?
How about an older, least favorite one.
Pull the pressure port or liquid port and install one of these:

http://www.wattco.com/files/product/pdf/Cartridge_Heaters.pdf

120v/400w

You'd have to come up with a fitting and ferrule to seal it to the(a) dip tube.
Keep the corny blow-off intact.

If the corny was needed in the warmer months, you could reuse it after a good cleaning.

I've only seen pics of the corny interior, so I may be out in left field.

'da Kid

I did just buy a mess of kegs I havent inspected yet, so maybe there is one in there that isnt in the best shape. These cartridge heaters look pretty cool, im sure I could get a fitting cut at a machine shop that will let me screw it onto one of the corny's posts.

I don't know how this will work in your area but I am in South Texas and try to keep my chest freezer cool for 10 months out of the year. Last winter we were only going to have temps in the 50's for a few days so I left my freezer plugged in to the thermostat and put a heating pad inside the box. The heating pad was just enough on low to keep my temps up to the range I wanted.

Whoever came up with the heating pad idea was just genius. Soft heating is great. I fooled around with light bulb in a can, but it would take up the space I need for a 5 gallon fermenter. Like any other heat source, it does take time to heat the fermenter, but the heat gain is slow enough to not cycle the compressor turning on and off.

I know I am kinda late to the game here, but bored at work and reading through a bunch of old threads. I have a very small space heater with built in fan that I picked up for under 20 bucks that lives in my chest freezer. It is on a dual stage controller and works great for maintaining the temp when I want it warmer or it is cold outside. I also like that it provides a gradual heating to the beer. When I know the temp of the beer is stable I just take the probe and bubble wrap off the carboy and expose it more to the air temp in the freezer. If the beer is at 68 and I want to raise it to 71, the heater will quickly bring up the ambient temp to 71 and the beer will then slowly rise to that temp. I use this for raising my saisons from low 60's to high 80's all the time.

I use the old "Light bulb in a paint can" heater (total cost: $7), it has no trouble keeping my fermenter at a balmy 70 degrees even in the depths of winter. I can't say I recall it getting as cold as -25, but it's gotten below 0 and held its own without issue. I would bet it'd work fine at -25. As long as the freezer is well sealed and the insulation is in pretty good shape, I'd guess you'd do just fine with this simple solution. Worst case scenario: it doesn't keep up and you're out $7.

In case you're not familiar with what I'm talking about, here's an example