I have four carboys in the closet and four in my bedroom on account of doubling production. The carboys in the bedroom have towels wrapped around them to prevent sunlight from hitting them.

I ought to purchase better drapes, but in the meantime, is it ok for me to wrap a Fermwrapped carboy in a towel? Edit: I am referring to safety and efficiency.

Edit: Another thought: I have all the cardboard boxes which the carboys came in. Can I place them upside down over the carboy if it is wrapped in a fermwrap? (it is tall enough to fit the airlock).

Here is what I am worried about the most:

I am using a Raspberry Pi with a commercial relay device (PowerSwitch Tail II) to monitor the temperature of the beer and turn on and off the Fermwrap if the temperature of the wort gets too low or too high, respectively.

I am in the middle of programming it so that:

I initially set the minimum temperature to 30% of the "optimal temperature range" and the maximum temperature to 40% of that range, meaning the fermwrap will turn on if the temperature is under 30%, and turn off if over 40%.

In the event that the temperature of the wort goes way higher than I anticipated due to the insulation effect of the towel/cardboard, the minimum and maximum range should decrease by 5%.

In the event that the temp of the wort goes too low, increase the minimum and maximum by 5%.

I'm worried that if I don't program this correctly, the temperature of the fermwrap could possible get too hot and a) ruin the beer; but more importantly b) present a firehazard to the towel or to the cardboard.

1 Answer 1


I've wrapped towels, insulation, and lots of other things around a FermWrap without issue. I like to use mine for sour-mashing, so I'll place a FermWrap around a boil kettle, then use a heating blanket to help give it insulation and an extra heat boost. There have been no adverse effects, and nothing has caught fire yet, so I wouldn't be too concerned about wrapping a towel over it.


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