The topic of keeping a constant temperature inside a fridge fermentation chamber/keezer/kegerator appears to pop up regularly. Using a dual temperature control (in my case an STC-1000) there are several common solutions for heating inside the fridge, from DIY projects

  • Light bulb (with paint can)
  • hair dryer
  • water bath + aquarium heater

to 'plug in and go' methods

  • heading pad
  • brew belt
  • space heater

and of course

  • no heating element at all

My question is how to do this in the safest way. Clearly the final option (no heating element) is the safest, but this may compromise the quality of the brew.

So assuming that I am using a heater, and my temperature controller malfunctions and leaves the heater on, which method (of the above, or other) is the best protected from causing a serious electrical hazards?

  • Another option is a ceramic heat lamp, as sometimes used for reptile enclosures.
    – jsled
    Commented Aug 12, 2015 at 13:38

4 Answers 4


I use one of these seedling heat mats as my heat source inside a freezer. They're built to have stuff sitting on top of them, they're water resistant, and they heat gently. Seems pretty safe to me.

That said, you can make any of these options much safer by plugging your temperature controller into a GFCI outlet.


The aquarium heater is probably the safest. The ones I've used before have their own controller, they're probably fairly reliable (nobody wants poached fish in the aquarium). Along with the water bath, you'll get good heat transmission without much hysteresis.

Assuming you have reasonable insulation, and you're not brewing in the artic, <100W should be needed.

The hair dryer is far more heat than you need. And if the controller failed, it would damage the beer.


I use a reptile heater bulb that uses infrared radiation for heat. Works great, no light to skunk beer, very safe.


I have a heating blanket for Saison.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.