RIMS Thermocouple in Mash tun?

[mtpratt]

Hey everyone

I have read alot of forums saying that the best place to put the thermocouple when using a pid rims tube is after the rims tube. I was wondering if putting the thermocouple directly into the mash tun, being it measures 8 inches, would work as well?

Thanks for any inputs.

 

[krazydave]

I wouldn't. Reason being that a mash isn't necessarily the same temp throughout the grainbed, Also, if your thermocouple is reading the temp lower in the grainbed than the very top, its going to read a lower temp until it eventually heats up to your set temp (since the hot recirculating wort is entering at the top and working it's way down). So by the time your thermocouple hits your set temp, there's a very good chance that the top part of your mash will already be over the temp you're aiming for.

Granted PID's can auto adjust to a system, but since every mash is different, I don't think it'd be able to adjust accurately.