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Heating Pad For Fermentation

So I was forced to move my fermentation bucket from my second bathroom to my basement because we had “people coming over”. No need freaking them out too with my constant airlock sniffing. Moving my fermenter to my basement did pose a problem though. My basement’s ambient temperature has been hanging around 50F due to the return of a classic New England winter.

I knew the basement temps were not going to fit into my yeast’s optimal fermentation temps (65F to 70F)…so after 7 days of rocking a constant 68F…I had to figure out a way to keep the bucket in the right temperature range in the cold basement.

First, I wrapped my fermentation bucket with a thick towel to keep in the heat the yeast was producing on its own. Then, I got an old heating pad, placed it on a chair, turned it on to the “Low” setting, and set the fermenter on top of it.

After 3 full days of using this set-up, I was able to keep the temperature of the bucket in the 67F-68F range. Nice.

Some my thoughts:

  • I set the whole thing on a chair so I get away from the cold concrete of the basement floor.
  • The towel also kept the heat generated from the heating pad from escaping
  • The towel also kept light out…no direct sunlight in the basement but we have fluorescent bulbs that probably aren’t good for a young beer.

The more I brew and the more I strive for making beer, I feel the next step in improving my technique comes from nailing down good fermentation procedures. Not sure if my makeshift heating rig really worked, but the thermometer is giving me good signals.


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  1. Travis

    All great ideas. My basement is a very sympathetic 64f most of the time. I have been keeping my fermentors off of the floor due to the cold concrete. The only yeast I found that didn’t do well in those temps was the Belgian Strong ale. With that I had to stash it up stairs in the bathroom (the brew wife was like “ew, you’re going to drink that after it’s been in the bathroom like that?”).

  2. Interesting. I have mine in our laundry room. We have a little cubby hole that’s the perfect spot for fermenting (if you look at the picture, I now have it shoved into the far right corner).

    The room stays at a pretty constant 68 degrees with it dropping a bit more at night. Occasionally, I put on a heater/fan across from the hole (not sure if that’s a good idea or not).

    The floor is cold and I wonder if I’d benefit from elevating it off the floor.

    I’m starting to realize light might be an issue as well. The laundry room/pantry gets a lot of use throughout the day with the light on a great deal of the time. I think I’ll wrap glass at least in a towel or sweatshirt.

    Speaking of fermenting in the bathroom, here’s the result of one gone bad: http://www.youtube.com/watch?v=EJM_n3jXPE4 (not for a weak stomach).

  3. Jim

    I have a cold basement, too – usually around 60-62 degrees F. To keep my ale fermentation temperatures in a yeast-friendly range, I do the following. I put a milk crate upside-down on the floor, and put a piece of cardboard on top of the crate. I put a reading lamp under the crate with a 40- or 60-watt incandescent bulb – depending on how cold the basement is. Then, I set the carboy on the crate and wrap it in a thick bath towel. I cover the whole works with a large cardboard box that has a footprint a few inches bigger than the crate and is tall enough to accommodate the height of the crate/carboy/airlock.

    I got cheap ($10) indoor/outdoor thermometer at the home improvement store and put the “outside” probe inside the cardboard box so I can monitor the temp of the air in the box. It records max and min temps, too. I use flaps cut near the bottom of the box and a couple on the sides near the top to vent the box to fine-tune the temp. It works great – max to min range is only about 3 or 4 degrees, and liquids don’t change temp as fast as the air, so it’s probably even a tighter range than that in the fermenter. The system consistently holds air temps between 68 and 72 degrees.

    I use the same setup to control bottle carbonation temps. I can fit 50 bottles into two milk crates. I just stack the crates of bottles where the carboy would have been and cover them with the same towel to keep the light off of them.

    As a safety note, the lamp is plugged into a GFI outlet, and there is a floor drain a few feet from the setup in case of a blowoff or other spill.

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