Originally Posted by Petervonstubb
I agree, I wouldn't submerged the probe. Just tape it to the side of the carboy with some sort of Insulation like bubble wrap. I cut up one of those cheap soft portable bag coolers they gave me for free from work. Your temp readings will be very close if not the same.
i don't understand why the probe is inside a jug of water. it looks like you are deliberately handicapping a very sensitive temp controller.
maybe you could just close it up inside an empty container. might be a bit more responsive to air temp fluctuations that way. or just hang it out in the open.
the air temp could get pretty warm or cold before the carboy water temp catches up.
i would also be concerned that it doesn't stay waterproof forever. i ruined a couple of oven probes by submerging them in my brew kettle.