Fermentation temperature control

[Bubbles]

Has anyone used a heating mat (for seed sprouting or for providing warmth in an aquarium for reptiles) in conjunction with a temperature controller to keep fermentation temps within a certain limit? For that matter, how about a heating pad or blanket with a temp controller?

I don't like the fire risk with light bulbs in paint cans in enclosed boxes, etc, but am looking for a way to heat my carboys without risking cracking the glass by applying too much heat in too small an area of the carboy (I've read that this happens).

My assumption is that there is far less risk of fire or damage to a glass carboy if you can apply heat in a more dispersed way. In that regard, it seems that a box with a heating mat or a heating pad/blanket over a carboy with some cloth insulation may be a more safe and effective method.

Any comments?

Thanks

 

[Nosybear]

I haven't - have never needed it. Which leads to the question of why do you need to heat your fermenter?

 

[LarryBrewer]

My shed is unheated, so my fermentation chamber needs a heat source in the winter. I do use a light bulb in a paint can. The 2 stage temperature controller is on a GFI protected circuit. The can is a good 18" away from the primary fermentor, I have used buckets and better bottles, but not a glass carboy in there yet.

I'd be more worried about heating blankets wrapped around themselves burning up, than a light bulb causing problems. Newer heating blankets also have an auto shut off feature after X hours.

 

[Nosybear]

Why not use heat tape? An electric blanket won't get hot enough to melt plastic - no worries there. Nor will heat tape - it's safe to wrap plastic pipes in it and it's low-energy. Either way, if you have a reliable controller on it, neither heat source should ever get hot enough to melt a carboy....

The engineer's famous last words, right? But neither an electric blanket nor heat tape get all that hot so you should be okay. If you use glass you'll definitely be okay. I just wanted to be sure it wasn't someone worried about a two degree temperature swing in their basement before answering.

 

[Bubbles]

Thanks for the replies. First, I need a heat source since I live in a cold climate (Minnesota) and my basement temperature is somewhere south of 62F -- not great for some yeasts, good for others. In particular, I'm hoping to use heat to maintain warmer temps for those yeast that could shut down if the temp drops toward the end of fermentation, to get good attenuation and for strains that would do better at higher temps. Since I brew primarily Belgian Ales, the basement temp is, for the most part, pretty ideal. I've had good luck in applying heat via a heating pad over a well-insulated carboy to get excellent attenuation for some Golden Strong Belgians -- down to 1.002. But I don't like leaving a heating source unattended and without a controller.

And no, I'm not too interested in using heating pads/blankets either. I'd rather use a heating mat since they're designed to provided a low level of heat and appear to have less likelihood of getting too hot. I don't really need a lot of heat, just enough to get temps up a bit.

I hadn't thought of using heat tape. It may be something to investigate further since it sounds like it could be safe enough. I'm actually thinking of switching to either plastic buckets or PET carboys just because I'm tired of having to lug around those heavy and breakable glass carboys. So something that can provide even, low levels of heat would be the solution. Someday, maybe I'll have a (unheated -- I'm trying to spend the least amount needed) shed, but winter fermentation would still have to be indoors since it gets VERY cold up here in Minnesota. Not even good for lagers.

An addition question -- does putting a controller temperature probe on a plastic bucket or carboy and insulating it well (with styrofoam, bubble wrap, etc.) give you a good indication of the temp of the contents?

 

[Nosybear]

A 62° basement? You should be able to make some wicked Weizens! Mine hovers around 68 so I have to cool the fermenters, particularly for hefeweizen or dunkelweizen. Be cautious about where you measure: Yeast generates heat when actively fermenting so the interior of a carboy could be several degrees warmer than the surface.

 

[Bubbles]

Yeah, according to the Northern Brewer store staff, I've got a great opportunity to make Belgian Ales -- and that makes me very happy since that's my focus. To your point, what I've read is that a surface thermometer (stick on type) is fairly accurate for measuring fluid temps, especially if you cover it with an insulating material. I have wrapped my carboy with several layers of cloth from a painter's dropcloth as well as an old parka and found that the fermentation process raises the temp up into the low to mid seventies. So, from what I've gathered in reading "Brew Like a Monk", this is kind of like the tradition of letting the fermentation go according to the heat generated by the yeast. Still, I want to ensure that the last part of fermentation not be lost to the coolness of the air temp. I had looked into a controller with a probe that could be placed in a thermowell (not sure I've got the terminology correct), but apparently it's now incompatible with the thermowell. Once we get into late spring/early summer, the basement will warm up and I'll be switching to different beers that use yeasts that are better suited to temps in the low seventies. I've got about 7 batches of Belgians "cellaring", so I should have a great spring/summer drinking the rewards.

I'm thinking of doing a Weizen for a friend of mine, so it's good to hear that my cold basement is good for them as well!