Low Cost HERMS Heat
We are always looking for creative ways to adapt
equipment for homebrew.
This is a hot water tank out of an old BUNN commercial
coffee pot, one of the pots with a hot water faucet. The pot contains a 1500
watt heating element and a stainless steel coil. When new, the faucet water
was heated by the coil.
My thoughts are to fill the tank with tap water and to
pass the wort though the coil.
Our initial test worked great - we raised 3 gallons of
water from 58 degrees to 155 degrees in 20 minutes!
I wired the heater so that I could plug it into a wall outlet.
I filled the hot water tank with cold tap water.
Then I put 3 gallons of cold water in my cooler based mash tun and set up a
re-circulating pump to pump the water through the stainless steel coil &
back to the cooler.
Turned the pump on.
Plugged in the heater & set the thermostat to max
The water heated from 58 degrees to 155 degrees in 20 minutes
Then I tried regulating the temperature with the thermostat on the tank and
found that it is not sensitive enough.
What I Know So Far:
Good - the tank will have no problem keeping up with mash temperature
Good - it's compact and affordable
Bad - can't reuse the thermostat because its not sensitive enough
Good - Should be able to control the temperature with a Ranco controller
Also, the flow rate of the pump I used was too high but this is easy to
solve with the addition of a ball valve
I need to set-up the same test with a Ranco controller and post the
Then I need to do an actual mash and post the results
I have had no more free time to apply to this project and a fellow
homebrewer has volunteered to to pick this project up & make it work. I'm
sending him a couple of sets of parts this week and will post his results to
this page as soon as he has something.