Thermometer - What is happening???

[garwatts]

Strange phenomena...
Whilst brewing yesterday I filled the sample jar with warm wort, took the OG, put in my thermometer at the same time to make the necessary adjustments. As I slowly removed the thermometer from the trial jar the temperature increased from about 35C to nearly 45C? How can that be?

[Bobba]

Digital thermometer with water in the probe?
Stick it in a COOL (i melted mine) oven to dry it out

[garwatts]

Digital thermometer with water in the probe?
Stick it in a COOL (i melted mine) oven to dry it out

Yep been there, done that But yesterday I was using my bog standard mercury glass thermometer

[Graham]

Strange phenomena...
Whilst brewing yesterday I filled the sample jar with warm wort, took the OG, put in my thermometer at the same time to make the necessary adjustments. As I slowly removed the thermometer from the trial jar the temperature increased from about 35C to nearly 45C? How can that be?

Probably because glass thermometers are calibrated for a particular immersion depth, usually 76mm, and because like air, hot water rises and it will be much hotter at the top than at the bottom of your sample jar. Stir it thoroughly before taking the temperature measurement, but not with the thermometer.

[garwatts]

Strange phenomena...
Whilst brewing yesterday I filled the sample jar with warm wort, took the OG, put in my thermometer at the same time to make the necessary adjustments. As I slowly removed the thermometer from the trial jar the temperature increased from about 35C to nearly 45C? How can that be?

Probably because glass thermometers are calibrated for a particular immersion depth, usually 76mm, and because like air, hot water rises and it will be much hotter at the top than at the bottom of your sample jar. Stir it thoroughly before taking the temperature measurement, but not with the thermometer.

Thanks - will try that Graham - it makes sense but I have never noticed it before Also it's quite a temeprature drop fro 45 to 35??