The last batch of beer I made was the first I fermented in a temp-controlled chest freezer. I noticed that the colder air pools at the bottom as it spends long periods of time not running, which makes precise temperature control difficult. I'm wondering if the solution is as simple as putting a small fan in there to keep the air circulating, or if anyone has anything better/more creative they've done. I would also like the option of continuing to brew ales in the winter time. My basement is typically sub-60 for most of the fall and winter, so I need a warming element in my chest freezer to keep it at ale temps. The best thing I could come up with is putting an electric blanket in there and running it off of my temperature controller, but even if I had a fan circulating air in there, I'd be worried about spots getting too warm. So, what can I do?
I use a dual stage temperature controller on my fermentation freezer. The cool side controls both the freezer and a 12V case fan that's mounted inside. The hot side controls a reptile heating pad that hangs on the back wall of the freezer.
I don't know what else to say other than it doesn't matter where the cold or warm air pools, as long as your fermenting wort is at the desired temp.
"it spends long periods of time not running, which makes precise temperature control difficult" Compressors are not meant to run continually...the less they run, the better. You can adjust the differential on your temp controller (default is 5*F on my Johnson419)... 5*F should be fine. I'm convinced thermowells are overkill...set your control (for example) to 55*F (ambient) and note the fermometer reading. If setting at 55*F keeps the fermometer at 68*F, then I say good enough. It's kind of like calculating strike water temp...you have to know YOUR system...if you know what I mean.
Indeed! The wort is constantly being stirred by the fermenting yeast during the most critical period, so it'll stay pretty consistent throughout.
You're a 15 watt light bulb away from getting this done. I use this rig against a Johnson control outside in 20F weather. I hang it above the fermenter on a rack in the fridge. It keeps within 1F.
Excellent technique! Many people use a shoebox or other device to shield the carboy from the light, but I don't believe an incandescent lamp puts out the damaging wavelengths (perhaps someone could comment on this?)
Well, I think the issue is more that a chest freezer is designed to hold temps below freezing. And the compressor probably runs more often to achieve that than it does to hold a temp in the 50s or 60s. Is it worth investing in a probe to put inside the bucket? I'm not convinced that attaching it to the outside of a bucket gives a very accurate reading. But then again, maybe the real problem is that I'm still using a bucket.
Couldn't you place the carboy/bucket in a tub filled with water inside the freezer to stabilize the temp? i do this in my basement and it works great. Keeps fluctuating temps away from my beer since it takes longer for the water to heat and cool.
Oops. I forgot to mention that I ferment in ale pales. I guess I could see the point in the shoe box. As for grow lights, they have some differnt wavelengths, but I'd assume that regular lamps have at least some of the same wavelengths as the sun. Better safe than sorry here.
I would be very careful with any incandescent bulb and standard fixtures...not designed for high humidity/wet environments (like a chest freezer @ 60*F). It will work for some time, but there are better ways.
I would say the important thing is the actual temp of the fermenting beer, not the ambient temp, since there can be significant differences. To measure that I would recommend a thermowell, or at least attaching a probe to the side of the carboy and insulating it from the ambient temp with bubblewrap or some such. Since getting a thermowell I've done some checking to compare the ambient temp vs. thermowell measured carboy temp, and the difference is sometimes as much as ten degrees at peak fermentation activity. What I do, and this may indeed be overkill, is to set the ambient temp in the wine fridge I use for fermentation chamber to a temperature about 5 degrees below my intended fermentation temp, then attach a brewbelt heater to a temp control with its probe in the thermowell, setting the control at the fermentation temp.
I personally love my thermowell since I don't brew at home and don't have the luxury of going to my brew site as often as I'd like. The thermowell allows me to set my fermentation temperature and adjusts for me throughout fermentation, counterbalancing the exothermic contribution that runs highest 1-3 days into primary.
I like your method...but I think it works just as good without the thermowell and a fudgefactor applied. I usually find myself ramping up the temp a few degrees anyway about day 3 or 4 based on the bucket fermometer temp.
Didn't one of the BN podcasts do comparisons between thermowell and outside of carboy thermometers and found they read within 1dF of each other? I want to say it was a Brew Strong from 4-5 years ago.
