Where should I stick my probe? :)

[Bnewman]

I am in the planning phase of a RIMS tube build. I am wondering where the best place is to place my temp probe. I have taken temperature readings in several different locations throughout my brew system. Inside the mash tun, at the surface of the mash, inline just past my ball valve as wort recirculates. I can get a 5-6 degree swing between different locations. I plan on a very simple 120v RIMS just to hold my mash temp. So probe placement seems like it might play an important part in accurate temp controll.

My thought is the center of the mash tun. This way i am getting an average temp of the entire mash. Oh and by the way I have a 15 Gal keggel as a mash tun, and I plan to use a direct fire blichmann burner to bring strke up to mash in temp. I only mention this because I suspect that the bottom of the kettle might be a bit hotter at the beginning of the mash.

Any suggestions would be helpful.

 

[doug293cz]

By placing the probe feeding the PID in the center of the MLT, you are likely to have control lag problems. This is because you will be dumping hot wort somewhere near the top of the MLT, and it will take a significant amount of time before the temperature in the center of the MLT responds. By the time it does, you will have dumped too much hot wort into the MLT, and the temperature will overshoot. To prevent overshooting, you want to place the temp probe in the wort flow where it reenters the MLT after the RIMS tube. Then you will need to run your system and measure temps around the MLT to determine if you have a significant offset between the bulk temp and the temp at the probe. If so, adjust your PID setpoints to compensate for the offset.

Brew on

 

[Gameface]

What he said. This topic has been debated a few times and controlling on the rims output is the place to control from.

 

[slym2none]

Right in the mash-hole.

*whistles innocently*