Calibrating an STC-1000 at mashing temps

[Benn]

I have an STC-1000 that reads 0 degrees in an ice slurry, however when the temp range is between 60 & 80 degrees it reads about 4 degrees colder than the half dozen other digital temp gauges I've compared it with.
It's possible that the STC is correctly calibrated and the other cheap temp gauges are all wrong but I'd prefer to calibrate the STC for its intended use i.e mashing.
My question is, do I buy a quality thermometer from a kitchen shop and calibrate the STC against that at 65deg or thereabouts? or is the a better way?

Cheers,

 

[pcmfisher]

Who knows about the accuracy of a STC1000. Just because it is accurate at zero doesn't mean it is accurate at any other temp.
It amuses me that people insist on these units over others for accuracy because they read in 0.1 deg increments.

All you can do is check with other thermometers as you are doing.

 

[Ducatiboy stu]

It amuses me that people insist on these units over others for accuracy because they read in 0.1 deg increments.

EXACTLY. just because it can read and show small increments does not make it accurate

The prob would most likely be with the probe.

If you have 1/2 dozen thermometers that are fairly close and the STC is out, its a fair bet that the STC is actually out.

Old fashioned glass mercury/spirit ones are the best to use. They rely on good old fashioned expansion to show temperature which is always constant and linear

 

[crowmanz]

I have an STC-1000 that reads 0 degrees in an ice slurry, however when the temp range is between 60 & 80 degrees it reads about 4 degrees colder than the half dozen other digital temp gauges I've compared it with.

You don't mention what your other temp gauges read in the ice slurry.

What does the STC read at boil?

Sounds like the STC is out and needs to be calibrated if it is 4 degrees colder than everything else.

 

[JDW81]

My temp controller reads 3 degrees above my good quality lab spirit thermometer at mash temps. I just take that into account when I mash, and set my temp controlled on my RIMS tube 3 degrees under what I want to mash at. i.e if I want to mash at 65, then the temp controller gets set at 62. Easy peasy.

JD

 

[Benn]

Thanks for the feedback,
I placed all the probes in a makeshift ice slurry from the scrapings off the freezer shelves and the STC is reading about 1 degree lower than the rest. I'll check it at boiling temp tomorrow with a different NTC sensor as well.
Couldn't get hold of a quality thermometer today, so it's all preliminary for now.

 

[pcmfisher]

Thanks for the feedback,
I placed all the probes in a makeshift ice slurry from the scrapings off the freezer shelves and the STC is reading about 1 degree lower than the rest. I'll check it at boiling temp tomorrow with a different NTC sensor as well.
Couldn't get hold of a quality thermometer today, so it's all preliminary for now.

Yes, but as stated, with a stc the readings of frozen water and boiling water have little to do with the accuracy at mash temps.
As JDW81 says, check it at mash temps with another thermometer. Long glass ones are good.

 

[Ducatiboy stu]

The good thing about a long glass thermometer is that if it reads say 2*C out at 0*c in ice slurry, then it will read 2*c out across the whole range, unless the scale is wrong. But that can be easily checked in boiling water to see if it is out the same as at 0*c ( taking into account altitude )

 

[SBOB]

My temp controller reads 3 degrees above my good quality lab spirit thermometer at mash temps. I just take that into account when I mash, and set my temp controlled on my RIMS tube 3 degrees under what I want to mash at. i.e if I want to mash at 65, then the temp controller gets set at 62. Easy peasy.

JD

why wouldnt you just calibrate the controller so it matches?

 

[Ducatiboy stu]

why wouldnt you just calibrate the controller so it matches?

Cause that would be cheating ( and sensible )

 

[Benn]

I used a different probe and it seemed to make a difference, Now all my available temp gauges and the STC with the new probe read within 1 degree of each other from 0-65deg. As I mentioned before, I'll buy a quality lab thermometer rather than rely on cheap equipment to verify calibration.
I'll end up with a PID at some point but for now they're are a bit over the top for my requirements. I don't need to program steps or anything, I just want something simple that can maintain a set temperature.
Cheers,