It’s cold and wintery and there’s something about brewing yeast that is clearly some kind of cosmic prank: all the beers you drink in summer need to be brewed at cold temperatures (lagers) and all the hearty ales that you might drink in winter like a warm temp!
I thought it time to complete the fermentation fridge by giving it the ability to heat as well as cool (after struggling to brew a hefeweizen under an electric blanket in the kitchen!). My STC-1000 aquarium thermostat already has a heating and cooling side wired up so really all that is required is to put in some kind of heating element. I originally had a 28W lightbulb doing the job, but I didn’t really like the fact that I could burn my fridge down (I had a close call with an ominous brown discolouration of the liner) and the UV put out by the lamp is not exactly great for beer (it comes in brown bottles for a reason!) . So time for a proper heater…
There are two main styles available: a belt and a pad. Belts are cheaper and more efficient at heating your brew as they wrap around the side of the fermenter and conduct directly into the beer. But I brew inside a well-insulated fridge and rely on a thermostat taking readings of the air inside the fridge. Heat the brew and it’s going to overshoot wildly while the air inside the fridge catches up – I don’t want to use my beer as a makeshift radiator!
I went with a heat pad. It sits nicely in the bottom of the fridge a shelf or two below the beer so it’s heating the air and not the beer directly.
It’s only a 25W model. I figured that it was pretty much the same as the light bulb I’d been using. After watching it only increase temperatures incredibly slowly over a number of hours I began to get worried. But no need to – I had 40L of beer in the fridge and it takes a while for things to reach equilibrium. So if you’re wondering: a 25W pad is perfectly capable! In fact its low “seeping” power means that it doesn’t rapidly heat, trip the thermostat, overrun, plunge and then repeat over and over.