Thermometer Calibration

MyQul · Jul 2, 2015

I have another question for those of you with a scientific background ( I'm looking at you @McMullan and @DanST

). How do you calibrate your thermometers.

The internet tells me to put some ice in water, the temp should be 0C and then boil some water and the temp should be 100C. Well my thermeter is +3C out in ice and +1C out in boiling water so I just average them and assume it't overall +2C out.

The the internet also tells me to do one of the above and your good to go. So what's the best thing to do and how do you do it in the lab?

TheRedDarren · Jul 2, 2015

From a cheffing background and dealing with EHO's and all the hygiene paperwork etc, we always boiled water and checked for 100c then iced water for .1/.2 or so.
I checked my cheap wilkos thermometer and it was 2 out on ice and 1 our on boiling water, my digital was bang on the money top and bottom.

DanST · Jul 2, 2015

Short anwser from me, dunno sorry.

I check mine against the reference thermometer in work which gets sent off somewhere for calibration.

Tony1951 · Jul 2, 2015

MyQul said:
I have another question for those of you with a scientific background ( I'm looking at you @McMullan and @DanST ). How do you calibrate your thermometers.

The internet tells me to put some ice in water, the temp should be 0C and then boil some water and the temp should be 100C. Well my thermeter is +3C out in ice and +1C out in boiling water so I just average them and assume it't overall +2C out.

The the internet also tells me to do one of the above and your good to go. So what's the best thing to do and how do you do it in the lab?

You and me are thinking along the same lines today MyQul. I just stumbled on this thread of yours after starting my own in beer brewing discussions to set down something I just found out. I am going to bet that your thermometer is just like mine.... The victim of 'Driver Error'.

Follow the link to find out why.

http://www.thehomebrewforum.co.uk/showthread.php?t=54435

:)

MyQul · Jul 2, 2015

Tony1951 said:
You and me are thinking along the same lines today MyQul. I just stumbled on this thread of yours after starting my own in beer brewing discussions to set down something I just found out. I am going to bet that your thermometer is just like mine.... The victim of 'Driver Error'.

Follow the link to find out why.

http://www.thehomebrewforum.co.uk/showthread.php?t=54435

:)

Cheers Tony. If I could like your post twice I would. I've been having thermometer woes since I realized you need to calibrate your thermometer/they can be out of calibration.

My current thermometer it a digital one meat thermometer since I broke my last 12" spirit thermometer trying to calibrate it (put it in boiling water then ice water straight after :doh:

)

I'd love to be able to afford one of those ÃÂ£36 thermapens. Is your one with the 76 immersion the same this one?

http://www.amazon.co.uk/dp/B00IKJPN4G/?tag=skimlinks_replacement-20

Tony1951 · Jul 2, 2015

MyQul said:
Cheers Tony. If I could like your post twice I would. I've been having thermometer woes since I realized you need to calibrate your thermometer/they can be out of calibration.

My current thermometer it a digital one meat thermometer since I broke my last 12" spirit thermometer trying to calibrate it (put it in boiling water then ice water straight after )

I'd love to be able to afford one of those ÃÂ£36 thermapens. Is your one with the 76 immersion the same this one?

http://www.amazon.co.uk/dp/B00IKJPN4G/?tag=skimlinks_replacement-20

My Young's thermometer is a tad short of 12 inches - about 11.9 inches. I can't quite make out the detail from the photo of that link, but I doubt Young's are selling more than one ÃÂ£3.50 spirit thermometer of a nominally 12" length.

This is the ebay link I got my accurate digital probe from:

http://www.ebay.co.uk/itm/DIGITAL-K...-BBQ-MEAT-STEAK-TURKEY-WINE-JAM-/141684320770

It was ÃÂ£2.89 and is nicely made for the money. It also works perfectly at 100c and 0c.

Edited to put in correct link.

MyQul · Jul 2, 2015

I bought one of the thermometers from your link in the hope I get one as accurate as yours.

It seems a lot of the spirit type thermometers have an 'immersion line' like the wilko one. You can see it if you zoom in about an inch below the -20C line

I found this article on how to calibrate your thermometer using a calibration curve if your 'top' and 'bottom' readings with ice and boiling water are both out differently

http://byo.com/hops/item/412-calibrating-thermometers-techniques

Not sure my **** maths skills are up to it though

Tony1951 · Jul 2, 2015

MyQul said:
I bought one of the thermometers from your link in the hope I get one as accurate as yours.

It seems a lot of the spirit type thermometers have an 'immersion line' like the wilko one. You can see it if you zoom in about an inch below the -20C line

I found this article on how to calibrate your thermometer using a calibration curve if your 'top' and 'bottom' readings with ice and boiling water are both out differently

http://byo.com/hops/item/412-calibrating-thermometers-techniques

Not sure my **** maths skills are up to it though

Hope it works as well as mine then, or I'll feel responsible for adding to your thermometer woes.... :)

The top unscrews easily and you can replace the battery. Not sure how well it would survive being dipped too deep into liquid though, but it does seem to have some blue rubber seals.... I won't chance it mind. I dunked my electronic scale which went a bit mad until I left it in the sun for an hour when miraculously, it became all normal and boring again and just weighed stuff like it did before I spilled water on it.

Thanks for the link on calibrating. I'll read that after my tea (spag bol and small beer) - getting shouted at to feed the dog. It's like being in Kitchener's Army - you don't eat till the horses are fed.... :)

MyQul · Jul 2, 2015

Tony1951 said:
Hope it works as well as mine then, or I'll feel responsible for adding to your thermometer woes.... :)

The top unscrews easily and you can replace the battery. Not sure how well it would survive being dipped too deep into liquid though, but it does seem to have some blue rubber seals.... I won't chance it mind. I dunked my electronic scale which went a bit mad until I left it in the sun for an hour when miraculously, it became all normal and boring again and just weighed stuff like it did before I spilled water on it.

Thanks for the link on calibrating. I'll read that after my tea (spag bol and small beer) - getting shouted at to feed the dog. It's like being in Kitchener's Army - you don't eat till the horses are fed.... :)

It's only a couple of quid if it's ****e. If it doesn't work, I think I might bite the bullet and get a therma pen

Twostage · Jul 2, 2015

MyQul said:
It's only a couple of quid if it's ****e. If it doesn't work, I think I might bite the bullet and get a therma pen

:thumb:

It's really reassuring when you open the thermapen box and there's a certificate showing it's accurate.

MyQul · Jul 2, 2015

Twostage said:
:thumb:

It's really reassuring when you open the thermapen box and there's a certificate showing it's accurate.

I'd still test it in ice and boiling water though!

McMullan · Jul 2, 2015

MyQul said:
I have another question for those of you with a scientific background ( I'm looking at you @McMullan and @DanST ). How do you calibrate your thermometers.

The internet tells me to put some ice in water, the temp should be 0C and then boil some water and the temp should be 100C. Well my thermeter is +3C out in ice and +1C out in boiling water so I just average them and assume it't overall +2C out.

The the internet also tells me to do one of the above and your good to go. So what's the best thing to do and how do you do it in the lab?

That's a serious question, actually. Measuring temperature accurately is surprisingly difficult and very expensive. A genuinely certified calibrated temperature probe is not something I'd pay for to monitor my beers. So I don't. I use a basic alcohol thermometer as my 'standard'. It seems accurate enough in ice water and in boiling water. My digital 'thermometers', temperature control unit and cheap weather station sensors, are within about 1*C of my 'standard'. I can't calibrate them, they're set. For some reason the control unit is above the 'standard' and the weather sensors are below it. I make reasonable questimates, which seem to work. If I want my fermentation chamber at 20, I'll set the controller to 21. When the weather sensor inside transmits 19, I'm happy. The critical period, of course, is during vigorous primary, when the yeast are generating a surprising amount of heat. Then I'll set the control unit to 19*C until it doesn't switch to refrigerate so often, after about 2 days.

Twostage · Jul 2, 2015

MyQul said:
I'd still test it in ice and boiling water though!

So far I've resisted. I'm sure at some point I'll waiver and stick it in ice water and a pan of boiling water :smile:

Twostage · Jul 2, 2015

McMullan said:
That's a serious question, actually. Measuring temperature accurately is surprisingly difficult and very expensive. A genuinely certified calibrated temperature probe is not something I'd pay for to monitor my beers. So I don't. I use a basic alcohol thermometer as my 'standard'. It seems accurate enough in ice water and in boiling water. My digital 'thermometers', temperature control unit and cheap weather station sensors, are within about 1*C of my 'standard'. I can't calibrate them, they're set. For some reason the control unit is above the 'standard' and the weather sensors are below it. I make reasonable questimates, which seem to work. If I want my fermentation chamber at 20, I'll set the controller to 21. When the weather sensor inside transmits 19, I'm happy. The critical period, of course, is during vigorous primary, when the yeast are generating a surprising amount of heat. Then I'll set the control unit to 19*C until it doesn't switch to refrigerate so often, after about 2 days.

Having a standard is a good idea. I've got the luxury of two fermentation chambers so I've made it so the STCs controlling each read the same so I can transfer stuff from one chamber to the other. Simple matter of sticking both probes next to each other and choosing a master.

I suppose now I have a thermapen I should calibrate them against the new true (within .4C) master.:wink:

McMullan · Jul 3, 2015

Twostage said:
Having a standard is a good idea. I've got the luxury of two fermentation chambers so I've made it so the STCs controlling each read the same so I can transfer stuff from one chamber to the other. Simple matter of sticking both probes next to each other and choosing a master.

I suppose now I have a thermapen I should calibrate them against the new true (within .4C) master.:wink:

Sounds like a good plan. :thumb: I do like the STC. More functions than the ATC I use.

MyQul · Jul 30, 2015

Tony1951 said:
My Young's thermometer is a tad short of 12 inches - about 11.9 inches. I can't quite make out the detail from the photo of that link, but I doubt Young's are selling more than one ÃÂ£3.50 spirit thermometer of a nominally 12" length.

This is the ebay link I got my accurate digital probe from:

http://www.ebay.co.uk/itm/DIGITAL-K...-BBQ-MEAT-STEAK-TURKEY-WINE-JAM-/141684320770

It was ÃÂ£2.89 and is nicely made for the money. It also works perfectly at 100c and 0c.

Edited to put in correct link.

Well four weeks later my thermometer has arrived. It's only come from Barking I could have walk there and back and collected in person quicker.

On the upside it really accurate for a 3 quid thermometer. It's only 0.8 of a degree out,. Much better than the ÃÂ£10 meat thermometer that I bought from Argos. Was just about to pull the trigger (tommorow in fact) on a 37 quid thermapen. Will definately be putting that on hold. Cheers Tony :hat:

Demig · Jul 30, 2015

Interesting thread and reminding me of the boring task of calibrating thermometers at work some years ago! Some of those had to be done at 350c which is a hazardous operation involving hot oil.

Worth remembering that for the ice, the water for the ice and the boiling water you have to use distilled water. Using tap can give results which are out by more than you would expect in some areas. You can also take the atmospheric pressure into consideration but that's going too far [emoji3]

Demig

Tony1951 · Jul 30, 2015

MyQul said:
Well four weeks later my thermometer has arrived. It's only come from Barking I could have walk there and back and collected in person quicker.

On the upside it really accurate for a 3 quid thermometer. It's only 0.8 of a degree out,. Much better than the ÃÂ£10 meat thermometer that I bought from Argos. Was just about to pull the trigger (tommorow in fact) on a 37 quid thermapen. Will definately be putting that on hold. Cheers Tony :hat:

Wow! Four weeks! That's ridiculous. Mine came in about two days from the same supplier. he must have run out and reordered from China.

Glad you like it anyway. I certainly like mine. Don't get it wet. Mine stopped for three days when I splashed the electronic part with water while wiping off sticky wort. I had to take out the battery and leave it in the airing cupboard for a few days. I think the little switches got wet. They stopped responding anyway. All ok now it is dry.

Twostage · Jul 31, 2015

MyQul said:
Well four weeks later my thermometer has arrived. It's only come from Barking I could have walk there and back and collected in person quicker.

On the upside it really accurate for a 3 quid thermometer. It's only 0.8 of a degree out,. Much better than the ÃÂ£10 meat thermometer that I bought from Argos. Was just about to pull the trigger (tommorow in fact) on a 37 quid thermapen. Will definately be putting that on hold. Cheers Tony :hat:

I'd forgotten about this thread. The .8 degree out bit - is that at ice and boiling water temps ?

I know it's a bit more expensive but I really like my thermapen :-).

Must say I also like my ÃÂ£1.99 cheapo probes too - ideal for sticking in the mash, ignoring its actual temperature and just making sure it stays static. Actually my last mash went up half a degree

I assume there was a hot spot that averaged itself out.

Let us know how it goes when you use it in anger.

MyQul · Jul 31, 2015

Twostage said:
I'd forgotten about this thread. The .8 degree out bit - is that at ice and boiling water temps ?

I know it's a bit more expensive but I really like my thermapen :-).

Must say I also like my ÃÂ£1.99 cheapo probes too - ideal for sticking in the mash, ignoring its actual temperature and just making sure it stays static. Actually my last mash went up half a degree I assume there was a hot spot that averaged itself out.

Let us know how it goes when you use it in anger.

the .8 discrepancy is both at ice and boiling water temp so it seems the thermom is pretty reliable.

Used it today for the first time. The figures are a bit small on it and the buttons are teeny but overall very pleased with it. Much better than my argos meat thermom.

Thermometer Calibration

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