I am a swamp cooler guy, and this is my first winter brewing; therefore, I will need some water heaters and water pumps.

Here are my requirements:

I have plastic swamp coolers -- no burning plastic
Swamps are filled with around 5 gallons
For vacations and when I'm not home, I cannot have any fire hazard or other safety problem
The heater must be able to heat to the specified temperature, within a range of 1-2 F

Edit: as per the comments, I have purchased Fermwraps and used them in combination with the Johnson digital controllers. However, I will purchase a water heater soon to compare the two and answer this question when possible.

  • having submersed heaters and pumps is a complex solution - is using a simpler fermawrap or a heat pad not an option?
    – mdma
    Dec 9, 2013 at 2:55
  • Have you looked into aquarium equipment? It's good enough for fish... Dec 13, 2013 at 1:50
  • @MDMA would you be able to suggest a digital thermostat to use in conjunction with a Fermawrap? Dec 14, 2013 at 0:18
  • While not the cheapest, Johnsons's digital temp controller is very, very nice. Only complaint I have is that it is not a dual temperature controller, it can only do heat, or cooling at one time. I use them all the time for my keezer and fermwraps.
    – Scott
    Dec 19, 2013 at 17:34

2 Answers 2


I do winter ferments in a big plastic tub (called a "muck bucket") full of water. I put the fermenter in that and put a 65W aquarium heater in the water. If it's really cold, the heater runs 24/7. when it's not so cold, I out it on a timer to come on at the coldest parts of the day. With ambient temps in single digits, I can keep steady temps between 50-55F for lagers or 62-65F for ales. Reliable and inexpensive. Also, when the weather is warmer, I can take out the heater and put ice packs in the water for cooling. FWIW, you do not need 1-2F accuracy.

  • Hey Mr. Conn; How many gallons of H2O are in the muck bucket? Which brand of aquarium heaters do you use? Are they connected to a temperature controller to cut them off? From what I have read on the internet, many support the notion that temperature consistency (within 1-2F) as well as temperature control (within the optimal temperature range of the yeast) are both important. Do you disagree with the notion of consistency, that as long as it is in the range of the optimal temperature all shall be fine, or disagree with the need for consistency to be within 1-2F? Thank you. Jan 24, 2014 at 5:31

If you're brewing outside, you're going to have to forgo the pumps in below freezing temperature unless you plan on running that pump throughout the brew day, almost non-stop with hot liquid. From personal experience, I've had my march pump freeze up on me in the garage with the ambient temperature around 31ºF sometime between vorlaufing and chilling the wort.

As to heating your mash and maintaining a boil, heat sticks pose just as much of a safety risk as propane. Electricity and water/liquid can be a dangerous thing, so unless you are totally comfortable with working with electrical things (or know someone who is), I'd personally avoid it. You'll want a Ground-Fault Interrupt that you're plugging your unit into, sufficient service to power your heating elements, proper installation of your heat stick, and ensure that things are sealed sufficiently to prevent leaks and potential electrical hazards. But not being an electrician, I recommend that you consult with a licensed electrician before proceeding with that plan.

Personally, I recommend using a space heater of some sorts — like a propane-powered area heater to keep the ambient temperature above freezing. But be sure you have adequate ventilation or you could kill yourself with the Carbon Monoxide. For me, having the garage door up one foot usually works. I heat my mash and my wort with a propane burner, and when I need to rest for my mash, I wrap it up in two layers of the aluminum bubble insulation, held on with a bungee cord. I typically still have to heat and stir my mash every 15 minutes if it's below 30ºF in the garage.

EDIT: not sure I deserved the down-votes. Before the OP was edited, there was nothing to indicate the expressed desire was to control fermentation temperatures, and NOT winter brewing...which is what the content in his question implied.

  • Unfortunately, you seem to have interpreted the question as asking about "hot-side" brewing heating, not "cold-side" fermentation temperature management.
    – jsled
    Feb 23, 2014 at 18:00
  • There was nothing in his question (before he edited his question) that indicated this was about fermentation. I'm not sure I deserved the two down-votes because of a question that wasn't specific enough to spell out "I need help controlling fermentation temperatures."
    – michael t
    Feb 25, 2014 at 0:47
  • Fair enough. I've removed my down-vote, at least, fwiw.
    – jsled
    Feb 25, 2014 at 1:30

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