Fermenting Temp/Probe Help

[Theheadsn]

I know this topic has been done to death. But I haven't been able to really find an answer for my particular case. I have a medium sized fridge I use as a fermentation chamber (basically an apartment fridge). Right now I only have one 6 gallon carboy in there, and have my STC set at 20.0c (68f) with a swing of .5c (.9f). I have the probe tapped and insulated on the side of the carboy, but I don't like the long times the fridge has to run to cool back down the carboy, let alone the higher temps itll put off while fermenting will make it take even longer. I also am using the freezer section to hold some beer/spirits/glasses that I would like to keep cold if possible. I'm wondering if I took the probe off of the carboy, had it hang inside of the fridge, and just set the STC to say 16.5c-17.5c (62f-64f), if that would be well enough for my carboy to keep at a normal temperature. Least that way the fridge would not be running as much and the items in the freezer would stay chilled.

Some side information to help:
Brewing a Red Irish Ale
Used Liquid California V Ale Yeast WLP051
6 Gallon plastic carboy


Any insight would help a lot. I know general rule is tape it to the side of the carboy, but what happens when I add another fermenting carboy inside of there.

(btw not sure if I could do the whole probe in water thing because its not the metal probe it looks like black plastic/rubber. Not sure if thats waterproof or not)

 

[NCSU_Brewer]

I haven't done this type of setup yet, but I am a metallurgical engineer who has done a lot of heat treat studies, etc. I'd recommend a bigger hysteresis on your thermostat. 2 degrees is still plenty tight. Plus, unless you are using NIST-certified probes and wiring, you probably aren't able to measure temperature to within a degree of "actual" temp anyways.

So long story short, increase the "swing" range. If you could post a pic of your probe someone here might be able to tell you if it is waterproof.

 

[C-Rider]

I have a chest freezer w/an analog temp control I set it for 60* F and it's about 64*F with the probe laying on top of the bucket. I have no idea of temp swings but my beers come out pretty good.

 

[Zzyzx3]

So long story short, increase the "swing" range. If you could post a pic of your probe someone here might be able to tell you if it is waterproof.

I agree with increasing the swing range. I have mine set to a 2 degree range. The fridge doesn't kick on all the time and when it does, it isn't on for very long.

 

[Theheadsn]

Is there a reason I should have the swing temp higher? I would go from more frequent/quicker run times to less frequent/longer running times.

I'm really curious about having the temp probe just sitting out in the open. I may end up just biting the bullet to do it, but seeing as this is my first brew fermenting, I'm kind of pessimistic about it

 

[Brewsncrabs]

Do you have a fan running to circulate the cold air?
Is your carboy touching the side of the fridge if your coils are in the side?

Both of these things solved my temp swings in my chest freezer. Also added a thermowell for the probe, but not sure if that helped.

My Ranco is now spot on temps with no swings.

 

[NCSU_Brewer]

Is there a reason I should have the swing temp higher? I would go from more frequent/quicker run times to less frequent/longer running times.

The best analogy I can give you is driving your car. You can either punch the gas every time you accelerate and slam on the brakes at every stop light, or you can smoothly accelerate and decelerate. The second option puts a lot less wear and tear on your car. Similarly, less frequent/longer runs on your compressor will extend its life.

I'm really curious about having the temp probe just sitting out in the open. I may end up just biting the bullet to do it, but seeing as this is my first brew fermenting, I'm kind of pessimistic about it

(Keep in mind that my experience is with metal and high temperature). From my experience with heat treatment, the best ways to control temperature of a "thing" are:


1. Immersed in the "thing" (beer in this case)
2. Immersed in a smaller but similar "thing" (a suitably-sized jug of water)
3. Affixed to the surface of the "thing" (fermentation vessel)
4. Hanging in air (away from the heating/cooling source if possible)