Calibrated Digital Thermometer

Mackzee

I am looking for a calibrated thermometer to check the accuracy of other thermometers.

Can someone recommend a digital thermometer with a probe, with range of -10 to 120degC, accuracy +/-0.1degC. Also I want to be able to calibrate it myself in the future.

Thanks.

Mackzee

Any takers? It's actually not for home brewing.

mordeith

Mackzee wrote: »

Any takers? It's actually not for home brewing.

Sounds fairly hardcore. Not sure any homwbrewers would need to do that far for their own needs so may not have any recommendations. I know I'm happy enough with general temps although I'm not an all grain guy so could be talking compete arse!

Mackzee

I just want to calibrate at freezing and boiling. Surely some meat thermometers are out there that you can calibrate your self.

nsi423

mordeith wrote: »

Sounds fairly hardcore

TL;DR I would agree with mordeith.

Measuring temperature with 0.1°C accuracy - real absolute accuracy tracable to NIST standards - is not for the faint hearted.

Calibrating at known temperatures like freezing and boiling sounds very logical but in practice it's very hard to reliable achieve exactly 0°C (or any temperature for that matter) with that level of accuracy. You would need a better temp sensor to check your setup!

And even if you are happy with your two set points, you need a very linear sensor to maintain that accuracy across the full range.

I've worked with temp sensor equipment in the lab at work. We used a Triple Point of Water setup to check our temp sensors.
https://en.m.wikipedia.org/wiki/Triple_point
Not sure the cost of one of these, prob 4 figures. And that just checks accuracy at one known temperature.

Achieving 0.1°C sounds reasonable, sure even cheap digital temp sensors have displays showing 0.1 or 0.01°C resolution. But real accuracy down to 0.1°C is not easy.

I'm curious what the application is! Not many use cases really need that level of accuracy.

rubadub

Mackzee wrote: »

I just want to calibrate at freezing and boiling. Surely some meat thermometers are out there that you can calibrate your self.

I finally found a radionics one with an offset feature, so if measuring at a known temperature I could adjust it to match. But this does not mean if you test at 80C it will be correct at 0C. The real trouble is finding out what is a known temperature.

It would be a fluke (no pun intended! if you know your brands) that boiling point of tap water or steam will be 100.0C anyway.

https://journals.sagepub.com/doi/pdf/10.3184/003685008X360632

I don't recommend the radionics one. I just note the figures on a label on my thermometers and adjust accordingly.

In my tests I usually am genuinely interested to know what the boiling point of tap water is, on that particular day, that particular elevation, that mineral content, that vessel, that power source, that atmospheric pressure, that thermometer probe placement. I could not care less if its 99 or 100C. So I would also wonder what you are actually up to.

L1011

Most people attempting to home calibrate completely bugger up 0. And this is why high accuracy consumer units are not home calibratible.