How to a Add Thermometer to your Cooler Mash Tun
I bought a couple Rubbermaid coolers to use for my All-Grain brewing, but the one thing they didn’t come with was a thermometer. I had been using a digital probe thermometer until one brew session the temp was off by over 30 degrees. last time I checked water doesn’t boil at 185° in New Jersey. So after a bit of searching on the internet for cheap ways to add a thermometer, I found a forum on homebrew talk that used a rubber stopper and a simple probe thermometer to inexpensively solve this problem.
- 3/4″ hole bit
- 1/8″ drill bit (about half the width of the probe)
First Calibrate the thermometer(s). it is easier to do before the probe is on your mash tun or hlt.
Next, find where you want to place the therometer, make sure that it is in a location where the liquid will cover the probe, even with your smallest beers. Using the 3/4″ hole bit drill a hole through the outer skin of the cooler, then switch and drill from the inside out. This will way you’ll be less likely to crack or break the inner shell of the cooler.
Next drill a hole through the solid stopper with the small bit. You want it to be a tiny hole, the rubber will expand enough to get the probe through, but not enough to allow for a leak.
Finally put the probe of the thermometer through the cooler, and into the small end of the rubber stopper. The rubber stopper will go small end into the inner wall of the cooler. Keep pushing the stopper onto the probe and into the wall of the cooler until the fit is snug and the thermometer is up against the outer wall of the cooler.
Test for leaks and brew!