Fermenting Temp Method

I'm stoked!! I just recently bought a chest freezer and a Ranco temp controller to maintain proper temperatures during fermentation. I did an experiment first with a beer bottle full of water to see if the temp will be stable. I placed the thermocouple probe in the bottle and wrapped the top of bottle with saran wrap to immulate the real deal. I put the freezer at max and set the controller at 68 degrees. (The bottle of water was 100 degrees prior to all this) It dropped the temp of the water from 100 to 68 just like i wanted but one problem. When it reached 68 degrees and the freezer turned off, it was so cold that the water temp kept going down to 50 degrees.

Not good. Is this whats going to happen to my beer or will it stay closer to my set point due to the fermentation activity?

Please let me know your methods?

I've noticed this with my chest freezer also. Right now, its set to start cooling at 70 and turn off when the temp reaches 67. Even after it turns off, the temp drops down to 64 before beginning its slow rise.

The air in the freezer changes temp more quickly than the beer, so I think the beer is holding steady in the mid 60's (but I don't have any data to confirm this).

Once you get more stuff in your freezer, like 5 or 10 gallons of beer, the temp will probably stay more stable. In addition to beer, I also keep about 50lbs of grain in there, which should help to keep the temperature stable.

Another thought...If the freezing coils of your freezer are in the floor, you may want to keep your beer elevated a few inches. The coils in my freezer are in the walls. I can tell because that is where it is coldest when it is running.

skipdog,

After having my extra fridge break, I'm in the market for a smallish chest frezer to be used in the same manner as yours.

It's a bit off topic, but do you mind if I ask what/where/how much for the unit you're currently using?

Back on topic, I ran into the same issue back when I tested my old fridge. The effect was much less pronounced when using a larger 5 gallon batch vs. the small test growler I used. I set mine to about 2 degrees higher than the targeted temp and it all worked just fine.

I don't know how your system is set up but I think it will give you more stable temperatures if you leave the temperature sensor out of the liquid you're trying to cool. If you can get the air temp inside the freezer stable at 68 or whetever you want it at the liquid you are trying to cool will eventually get to and stay at that temperature. With the probe in the liquid and a large difference between the temp of the liquid and the temp you are trying to reach the freezer will cool down way below the target temp and shut off only when the liquid reaches your target temp. Since the air temp in the freezer drops much more quickly than the temp of the liquid the freezer will overshoot the target temperature. For better results either get your liquid at close to the temperature you want it at before you put it in the freezer or place the temperature probe outside the liquid.

an empty freezer doesn't hold temp the same way as a full freezer.

plus, it was the initially cooling.

fill it with beer and set your temp...it'll be fine.

fakeghostpirate, IMHO that was excellent advice. My 2 freezers opperate very nicely with the probes located at the center of the freezers.

OldFarmer said:

fakeghostpirate, IMHO that was excellent advice. My 2 freezers opperate very nicely with the probes located at the center of the freezers.

Click to expand...

I would agree that will work well as long as active fermentation is not taking place. In that case, I think it is important to have the probe measure the temp of beer whether it be directly in the beer or taped/insulated to the side.

I ran into this as well. I have had much better luck maintaining my desired temperature by taking my temperature probe out of liquid and just letting it dangle in the air inside of my chest.

To answer the question from Bassplayerr.

I have a 8 cubic foot chest freezer which i bought from lowes discounted at $120.
I can fit 2 fermenters in there. I purchased a Ranco temp controller on ebay for $55.

Thanks for the reply skipdog. I'll swing by my local Lowes tonight and see what they have.

Per Bobby_M
Whirlpool 8.9 cuft
$268 at Lowes
Capacity: (5) five gallon ball or pinlock cornies plus 3 gallon or 5lb CO2 tank on the compressor hump.
No wasted space. Kegs fit snugly. Smallest footprint possible for 5-keg system

It seems that everyone does it different. The choices are placing the probe in the beer or placing the probe outside the beer.

Do you think it will be more stable if you put the probe in the freezer measuring ambiant temperature, setting at 60 degrees to maintain a 68 degree beer temp?

Or would it be better to put in the beer. Not sure if the temps would fluctuate too much out of the range.

What do you think?

I just leave my probe in the middle of the freezer. I cool my wort to about 2-4 degrees below where I want to ferment at and pitch my yeast. The active fermentation will increase the temp a couple of degrees. I have had great beers with setting the temp on the controller to what I want and let the beer be until done. I am usually within a degree or two of what temp I wanted to ferment at.

Thanks for all the replies.....:rockin:

I have a theory about whether the temperature controller probe should be in liquid or left to dangle in the air.

If your cooling enviromentment is succeptable to wide variations in temperature, such as an old fridge in a hot garage, then you are better served by having the probe in the air. It's better to have the compressor cycle more often to maintain the correct air temperature to keep the liquids at the correct temperature.

You run the risk of running your compresser into the ground from all of that sprinting, but you'll have stable temps.

If you have a relatively stable ambient and a well insulated refridgeration compartment, it may be better to have your probe in a liquid that is closer in volume to your target liquid. Your compressor will work harder, but less often.

You run the risk of running your compresser into the ground from all of that hard work, but you'll have stable temps.

Poke it with a stick guys.