Temperature Controller Project

When I talk with prospective homebrewers, I always tell them the three most important things in brewing are 1) cleaning, 2) sanitizing, and 3) fermentation temperature control.

Cleaning and sanitizing are no brainers, and they are actually pretty straightforward to do.

But it took me a few batches to realize that because brewers make wort and yeast make beer, keeping the fermenting beer within proper temperature ranges helps the yeast make the best beer possible.

To that end, I've been doing very rudimentary temperature control. I invested in a 16-gallon rope handle tub a couple years ago. My fermenter goes in the tub filled with water just below the beer level, and I control the temperature of the water bath by adding ice or frozen water bottles. Because the temperature of the water bath is usually within about a degree of the temperature of the fermenting beer, I'm able to keep the beer right at the temperature I want - usually around 68F, sometimes down near 64F depending on the yeast strain I'm using and what I'm wanting out of the beer.

It's not a lot of work keeping the water bath at these temps, but I do find I have to check on the water temperature every few hours. I consider it a labor of love, but now I'm ready to take it to the next step: setting up a fermentation chamber.

The concept of a fermentation chamber is actually pretty simple. A chest freezer fitted with a temperature controller is a great way to go. You plug the freezer into the controller and the controller into the wall, place the temperature probe from the controller into the freezer, set the temperature on the controller, and it turns the freezer on and off to maintain the set temperature.

Getting the hardware together.
The knock out for the controller is
already rough cut here.

You can buy temperature controllers already wired and ready to go, but I decided to do it on the super cheap and buy one that I wire myself. With the help my favorite homebrewing forum and a handy YouTube video, I was on my way.

All wired up

The hardest and most time consuming part of the whole project was cutting out the holes for the controller and outlet. Drilled holes in the four corners and a coping saw got the rough cuts done quickly enough, but filing back the holes to where I needed them took about 30 minutes per hole.

Project finished!

The wiring was the easiest and most fun part of the project. Since I had good diagrams and was able to source color coded wires, it was a snap.

The total project cost was about $32: I grabbed the controller on a price drop for just under $17 on Amazon, and the rest of the hardware came in at about $15 at my local big box. Considering wired dual stage controllers can range between $100 and $300, I'm going to chalk this up to $100-$200 saved. Yeah, me!

Next step: buy a 5 cf chest freezer!