The Fermentation Chamber
I have been using my re-purposed fridge with an external temperature controller as a fermentation chamber for around six months now, so I thought it worth saying how I’ve been getting on with it.
I started off with a 100W bulb in a clip-on holder, then I managed to shatter that, so I replaced it with a 60W spot-bulb in the same holder. I wasn’t happy that it was hot enough, and it certainly wouldn’t be terribly efficient (a case of being more light than heat, perhaps?), so I bought a tube heater from ToolStation. With the tube heater it heats up a lot more quickly, so I’m very happy that I bought it.
I started with the temperature probe stuck to the side of the fridge on its supplied suction cup. I then tried it on the side of the FV, with better results. Now I also tape it to the side of the FV with some duct tape so try and get it even closer to the temperature of the wort.
Using the chamber has certainly made the fermentation temperature a lot more reliable, as I can just set it to 18C and it will sit there for the duration, through winter or summer. I can also be more clever about the fermentation: the recipe for Erdinger Weißbier called for starting the fermentation off at 12C, then gradually increasing to 18C over the first four days. This, of course, is a doddle when using the controller.
The only restriction I’ve found is with crash-cooling. I can set the controller to 1C, say, but the temperature probe taped to the side of the FV will show a minimum of around 5.5C. This is due to the fridge’s thermostat limiting the cooling; the air temperature is below the fridge’s minimum, but the wort doesn’t get down that cold in the time I’m allowing it, as there’s only few degrees difference between the air and the wort.
The only ways around this that I can think of are either disabling the fridge’s thermometer (which I don’t fancy trying to do), replacing it with a freezer (maybe, one day, when we change our kitchen appliances, but not today!), or somehow making a better thermal connection between the back wall of the fridge and the wort.
It’s this latter that I’m contemplating. There must be a simple way of doing it, maybe using copper to conduct heat away from the FV…
The Temperature Controller
The temperature controller I use is the ATC-800+ I described in the original fermentation chamber post. I’m very happy with it, it was quite easy to wire up, it’s simple to use, and it seems reliable.
I unplug it when I brew so I can move it from the fermentation chamber to use it to control the HLT during the mash – it’s far easier than trying to hit the correct temperature by thermometer.
I’ve also just bought a cheaper equivalent, the STC-1000, to use with our beer fridge (which is an old under-counter fridge of my parents) from a company in Hong Kong, which I found on eBay. This is a lot more compact than the ATC-800+, but was just as simple to wire (exactly the same, in fact), and actually even more flexible in use, since it covers a similar temperature range but can be set to a resolution of 0.1C rather than the ATC’s 1C. I have it maintaining 14C +/- 0.5C, which seems idea for the beers we’re keeping in the fridge.
The only (current) downside is that I got the ATC supplied with a mounting box, but the new mini-TC doesn’t come with one, so the wiring is sitting exposed behind it on top of the fridge. Far from ideal, but given where it’s sitting it’s no danger, though I do intend to get a box for it as soon as I can find a suitable one.
I’m very tempted to get another of these mini-TCs to use with the HLT. Maybe when I found a decent mounting box for it!
