So, after a thread here I bought a temperature controller and have been brewing in a small chest freezer.



I've made a couple batches of "inmate brew" apple wine using a cheap Mr. Beer fermenter to screw around with (pumpkin version is in there now), and Just completed an India Red Ale (which turned out great!) using my 5 gallon glass kit (so much better than Mr. Beer)



That said, I've always wondered about how consistent my temperature is using a freezer and a temperature controller.



Then, the other week, I was rummaging around through my computer stuff and remember my data acquisition system.  Yes, I have a data aquisition system.



So, I went online, bought a cheap thermistor, got some old wire I had laying around, made a Labview program, and in a few days I was up and running.













So now, I present to you...a graph of the air temperature inside my chest freezer.

I was surprised at how much it actually fluctuates!



Don't worry too much about that low temperature in the beginning...I turned the freezer on when I was "brewing" (if you can call it that with this...."stuff") and forgot to put the temperature controller probe in there....no unfermented alcoholic beverage was in there at the time.



I realize the thermal mass of the liquid is higher than the air, and that the mean temperature is probably more important than the extremes (mean is 67.4, max is 70, min is 62).





But, being a novice at brewing still I wondered what you guys think of this kind of temperature profile.



Am I right to keep it on the low end as opposed to going above 70?



Is this kind of changing air temperature bad for my brewing?  If it is...well, I don't think there is much I can do about it.
And yes, I'm a nerd and a noob.  Feel free to make fun of me if you wish.





I plan to make a stout within a month or so...so we'll see how that changes the temperature profile.

put in a computer fan, throw in a couple buckets of water(more thermal mass), get it to temp, the add beer
that will  smooth out the curves



ETA some temp controller you can control the delta in which the the controller will shut on/off. If you make it less, it will cut on/off more but it will be more constant.
 

Curve looks right.  You can likely control the swing.

Its on the minimum setting right now +-1 degree.
It seems by the time the air temperature reaches the value where the controller kicks off the sides of the cooler are cold enough to push the temperature down farther even though the compressor is off.
Didn't think about a computer fan. I have some laying around somewhere.
The water is a good idea.  For using a small fermenter it makes allot of sense and should help allot.
When I use my 6.5 gallon glass big mouth bubbler it takes up most of the freezer.  I might be able to put a couple gallons on the side, but that's about it.  I haven't been able to get the temperature profile of that yet.  Probably will be a couple weeks before I brew again.
 

Just tape the probe to the side of your fermenting vessel with insulation of some kind (foam/whatever) to the air.

Dicking around with air temp or ambient gallons of water is a waste of time when you have that option.  Fermentation gives off heat.

More important is a steady temp, not the mean--always trend the temp upward when its about done fermenting.

Build a collar for the top with 2.x6s. This way you can drill a hole in the wood for tubes/wire.

Well, I was worried that the +-1 degree swings of the fermenting vessel would be worse than swings in air temperature.



I am testing it right now (with the temperature probe taped against the vessel with a rag as insulation to the outside air, and the temp controller probe in the air, as before).



We'll see how that changes things.



 

Nice.