I have brewed a few dozen batches of ale, but I'd like to brew a lager and am considering low-cost equipment to purchase. I see many using a chest freezer with a temperature control device (such as described in this question and this answer), so that's what I'm considering first.

However, I'm concerned about the reliability of a freezer when "harshly" power-cycled by something of the style of this device. It plugs in between the outlet and the freezer, and seems to work by turning on or off the freezer by essentially "plugging in and unplugging" the freezer to keep the contents in the right temperature range.

On compressor-based systems (refrigerators, dehumidifiers, air conditioners, etc.) I see warnings against "harshly" power-cycling these type of machines: it seems to imply that plugging and unplugging the system is somehow "bad" for unspecified reasons, and (based on the behavior of, e.g., unplugging and re-plugging a dehumidifier) it seems that some systems have some logic to avoid frequently turning on and off the compressor.

Should I be concerned about this at all? From your experience, have you seen any reliability (or other) concerns regarding this type of power-cycling? I'm surprised that I can't find other questions about this, so perhaps I'm just over-thinking this.

  • I was also considering posting this on Home Improvement for the power-cycling concept itself, but due to the application (brewing) I figured I'd get better "anecdotal" responses here. I didn't see similar answers there, either. If recommended, I could delete this question and ask there.
    – hoc_age
    Commented Sep 17, 2015 at 14:27

1 Answer 1


Yes, if you switch your freezer on and off in quick succession the compressor gives up the ghost and you have a box that can actually turn into a semi-oven.

Good news! thermostats like the STC-1000 have a timer (that you can set) that tells it not to power on/off within that period. I have mine set to 10 minutes.

When you buy a temp control device, just check if it has some delay or timer.

Happy brewing!

  • 1
    So the crucial element is the time between turning off and turning back on -- rather than the "sudden-ness" in some sense of it turning off or on. Is there a magic duration between on and off? 10 minutes is simply a conservative-enough duration?
    – hoc_age
    Commented Sep 18, 2015 at 13:17
  • 1
    Yes. even the internal workings of a fridge just shuts off the power to the compressor. Or just switches it on. There is no "soft" power on/off. :) I believe the manual of the device will give an indication of the delay between power off and power on. Commented Sep 18, 2015 at 13:20

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