An Improved Method for Monitoring Mash Temperature

[Reustonium]

I want to share my method for monitoring mash temperature more accurately and with (arguably) less hassle.

I'm in the process of developing an automated HERMS brewing rig, as a preliminary step I've created a mash monitor program which I've introduced in the thread HERE.

Tonight I brewed an ESB and I used the mash monitor for the first time. Here is a picture of my hardware, a Labjack U3-HV. For sensors I'm using two zenner diodes (LM335)

These are the same chips that are sold in "temperature sensors" commercially for ~$30/ea. They can be made for ~$5/ea if you are willing to do some soldiering.



Here is a shot of my display midway through the mash. As you can see I missed my target by a little bit. A potential point of error in sensing is that I had the sensors inserted into a thermowell which just sat in the mash. Since the thermowell will be installed in a SS mashtun, I didn't want to mess around fitting the thermowell into the side of the igloo cooler.



Lastly a shot of my temperary brewing setup with my new 60qt SS kettle, it rocks :rockin:



Here's the raw data


Thanks!

 

[kmk1012]

Dude, you have way too much time on your hands-I'm so friggin jealous! Looks very involved, I wish I was smart enough to do something like this-looks good!

 

[Snowhere]

I like the idea of an accurate temperature sensor as I know all my thermometers are off. And since I am at altitude, 8000ft, I can't go off my boiling point to calibrate them. So if nothing else I will be able to calibrate my thermometers with the LM335. I looked around a little for a thermowell, but found industrial ones that were expensive. What are you using for your thermowell and where did you source it?

 

[Reustonium]

The thermowell's are from Brewer's Hardware.

I was interested to see that there were some moments where the two probes disagreed by a considerable amount.

In a more permanent installation I will use thermal conductive epoxy to fasten the sensor in the thermowell, hopefully that creates more accurate measurements.

 

[kpr121]

And since I am at altitude, 8000ft, I can't go off my boiling point to calibrate them.

Can you not calculate the temperature at which water boils at your elevation? Heres a calculator that does it for you http://www.csgnetwork.com/h2oboilcalc.html

A quick check at 8000 feet shows that your water will boil at 197.3 F. Use that to calibrate your thermometers.

Or do what Reustonium did, it is much sweeter!!