Heating mat position?

[marc1138]

So, I've got a 24 watt reptile heating mat that I picked up at the pet store. The ambient temp in the house is starting to drop to the mid 50*F range as the weather gets cooler so I need a warming option for my ales. I have a dual stage temp controller and use a chest freezer as my fermentation chamber.

I'm wondering if anyone uses a heating mat, or similar device, how do you utilize it? Underneath with the carboy/bucket just sitting on top? Or strapped to the side, wrapped around the fermentation vessel? Or just near it to raise ambient temp and indirectly heat the wort in an enclosed space?

I use 6.5 gal buckets for fermenting if that makes a difference.

 

[SanPancho]

I wrap my carboys with heating pads. If you put it on bottom of carboy then insulate it from the cooler surface.

If you want to heat the entire chamber then add a computer fan. It will generate some heat as well as equalize temps throughout the chamber.

 

[PADave]

I set mine on the hump in my freezer. On the pad sits a couple gallons of water that are in the freezer to act as a heat sink. So to answer your question, indirectly.

 

[SanPancho]

I set mine on the hump in my freezer. On the pad sits a couple gallons of water that are in the freezer to act as a heat sink. So to answer your question, indirectly.

But no insulation between the pad and the freezer surface? You have a cooling surface in contact with a heating surface. They’re fighting each other. Seems.....inefficient.

 

[Craigmn]

One would be off while the other was on so they wouldn’t really affect each other

 

[SanPancho]

Right. I wouldnt go so far as saying they wont affect each other- the cooler walls are where the cold resides. But youre right they wouldn’t both be on at the same time.

my wife bought a bunch of cheap cork 8” rounds at ikea, the kind you put under a pot so it doesn’t burn your table or countertop. Once the wort reaches pitch temp I use them under the carboy. The fan blows the cold air around which does the cooling instead of surface contact with the freezer. The big temp swings i was getting pretty much disappeared once i broke the cooling surface contact. Might have something to do with the fact i do half batches. Either way, it was a noticeable difference in temp control.

 

[PADave]

But no insulation between the pad and the freezer surface? You have a cooling surface in contact with a heating surface. They’re fighting each other. Seems.....inefficient.

The heat doesn't come on during active fermentation, no need, the yeast make plenty. Only time the heating pad comes on is when I want to raise the temps towards the end of fermenting to finish out.

 

[marc1138]

Thanks for the replies. I ended up securing it around the bucket. So far so good. It's maintaining my target temp by about .5*F.

I figure that the other methods suggested would work just as well. There's more than one way to skin a cat, or in this case, ferment a beer. Cheers.

 

[ncbrewer]

I use a seedling heat pad - I think it's the same as your reptile heating mat. I asked the manufacturer if it would be ok to set the fermenter bucket on it. They advised against it, but didn't say why. I assume they were concerned about too much heat build-up with the pad sandwiched between two surfaces. So I tie it around the swamp cooler tub.

Some of the above posts seem to demonstrate that having the fermenter sitting on it is ok, but I still wonder if there might be a problem some time in the future.

 

[JimboMarimbo]

Sorry, old post I know, but worth adding that using a seedling heat mat wrapped around the fermenting bucket works well and maintains a healthy 20-25 degC even in the (English) winter - the caution touched on above I would echo; I started by placing the fermenting vessel on top of the mat, this worked well and I left it on and off for some weeks - however, when I came to finish and empty the vessel, I found that it had ruined the laminate worktop with a bulge and surface lift near the edges. I'd stick with the wrap method unless you have a solid stone worktop.