Recirculating mash: temp probe at top of pot, will this denature enzymes?

[renthispace]

I'm in the midst of my build, I had a thought.

I plan on having the temp probe at the top of the pot similar to high gravity's. With the temp probe at this location, the mash will see the correct temp of the pid as the probe is after the heatloss. If say you had the probe within the kettle or at the outlet of the kettle, the return wort would have cooled below the setpoint due to heatloss from the tubing and the pump.

The thought that just occurred to me is with my planned setup, the wort in the kettle near the element will be at a higher temp than my setpoint. Will this be a large temperature difference? How much heat is actually lost in the tubing while recirculating? And the best for last, will this denature or even change the actual mash temp since the wort is hotter at one point in the system?

 

[andhou27]

The difference should only be a matter of a few degrees and should give you an accurate enough reading. You shouldn't have to worry about denaturing.

 

[Sideways]

If you are concerned about heat loss you can always locate your temp probe on the return after the pump but just before it returns to the top of the mash. If you place the probe at the top of the mash in the kettle you will see greater temp swings near the element. I would place a second probe at the bottom of the mash just to be able to monitor what is going on in your setup at that location.

 

[jeffmeh]

If you haven't built it yet, why not put the probe in a tee on the kettle output? I don't think it will make a huge difference, but you won't have to worry about denaturing enzymes.

 

[renthispace]

If you haven't built it yet, why not put the probe in a tee on the kettle output? I don't think it will make a huge difference, but you won't have to worry about denaturing enzymes.

Putting the probe on the output would mean the return water would be cooler than the set temperature. I think I'm just over thinking this whole thing but neither spot will be perfect. There will be a temperature difference somewhere, hopefully it will be negligible.

 

[ChuckO]

I would put the probe in a tee at the kettle output. Measure the temperature as you return it to the kettle a few times and verify the heat loss to reassure yourself that everything is OK. I have found that the heat loss from my kettle through the pump and back to the kettle is on the order of 0.5 to 1.0 degree depending upon flow rate, higher flow = lower loss. If something starts to go wrong I would rather not have the wort overheat.

 

[acidrain]

why not put the probe in a tee on the kettle output?

I would put the probe in a tee at the kettle output.

Did you guys mean at the return port? That is the generally accepted place to put it.

 

[jeffmeh]

Did you guys mean at the return port? That is the generally accepted place to put it.

You are recirculating from the kettle output to a port through the lid of the kettle, correct? That is what I mean by "kettle output." As I said, it probably won't make much of a difference either way, and it would be easy enough to move the tee if you want to change it over. Check temps at both places with a handheld thermometer, check various locations in the mash, and see which probe location best represents the mash temp.

With the heating element low in the kettle, the temp at the kettle output should read higher than that at the lid, because of heat loss through the tubing. You can insulate the tubing to reduce the heat loss. That said, heat in the kettle rises, so the top of the mash will likely also be hotter than at the return through the lid. If you can recirculate fast enough (this depends upon how fast the bag will drain and can be impeded by the basket), the temps should be fairly uniform throughout.

Once you find the probe location most representative of the mash temp, you can always adjust your setpoint a bit to compensate if you must.

 

[acidrain]

Ah, it's not a RIMS... I didn't get that until just now.
Regardless... seems like putting it at the top after cooling from the pump and the lines would be the place to take measurements... just like shown in his example.