Multi-Purpose Fermentation Chamber


Looking back on my early years of homebrewing I can quickly recall the one improvement I made to my brewing process that took my beer from “meh” to “ooh, I didn’t make enough of this one . . .”

This wasn’t a particularly complicated or expensive upgrade either. As a matter of fact, I had picked it out of my neighbor’s curbside offerings one evening after work. If it wasn’t for the note left which simply read “Works,” I probably would have passed by this opportunity and who knows, my homebrewery may have never reached its full potential.

Prior to that find, I tried every option out there to keep a steady temperature for my yeast buddies. A giant bucket of water with ice packs, in the tub with wet towels, close to the radiator, far from the radiator, in the closet . . . you name it. They all seemed to reduce the swings in temperature, but they left much to be desired. On top of that, the house I was living in was drafty and in the wintertime I’d have a hard time keeping fermentation temperatures in the mid-60s °F (~18 °C). Placing the fermenter near the radiator to maintain fermentation temperatures or for a diacetyl rest would help, but some mornings I’d often find my wort temperature had plummeted after the heat had shut down overnight. I’d have my fingers crossed that the temperature plunge didn’t shut down my yeast leaving me with an under-attenuated beer.

Sadly, that first refrigerator didn’t survive a house move I made, but shortly after parting ways I came across another similar opportunity when a friend was cleaning out a relative’s house. I had several modifications I wanted to make to provide me with a truly controlled environment.

I had several key objectives for this build. My primary goals were to create a fermentation chamber that was capable of simultaneously controlling both heating and cooling (dual stage), was multi-functional space, could be easily kept clean, and lacked wires running amok in the chamber. I had several secondary goals too. First was that I wanted to over-ride the thermostatic control in the fridge, not simply cut power to the whole unit like many fermentation controllers do when turning on and off. Also using my BCS-460 unit as a controller would allow me to maintain specific temperatures with targeted and timed increases and decreases in temperature during warmer and colder months. Finally I wanted my BCS-460 unit to control both my HERMS brewhouse and cellar. So this fermentation chamber needed to be controlled by a modular unit.

By overriding the thermostatic controls of the fridge, my BCS-460 tells the fridge when to kick on and off. For heating, I used a Ferm-Wrap™ unit that I installed into the air circulation duct located in the back of the fridge. This allows air to pass over the heating element, increasing its efficacy. By over-riding the fridge’s thermostatic controller, other components like the interior light and fan have power even when the cooling unit is not turned on.

And by keeping this chamber as a storage place for vital brewing supplies and parts that are often needed quickly during a brewing session, allows it to be multi-functional for my needs. Optimizing work space is often underappreciated, and difficult to maintain at times, but does help set the stage for an efficient brew session.


  • (2) 25-amp solid state relays (SSR)
  • Heat shrink butt splice connectors
  • Heat shrink spade connectors
  • 3 male aviation cable connectors with an appropriate number of female connector panel mounts
  • 24” AWG 12 THHN stranded wire for heating and cooling
  • AWG 18 THHN stranded wire for signal wire from BCS
  • PVC or aluminum housing for relays
  • Ferm-Wrap™ heating wrap
  • Upright refrigerator/freezer with room for fermenters
  • BCS-460 (or other PID temperature control device, there are manyto choose from e.g.. BrewPi/STC-1000)