Using an Infared Thermometer (with Behmor)

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
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Postby Benjammer » Aug 24, 2012, 2:41 pm

I was just wondering if anyone had thought of the idea of using a infrared thermometer to monitor roast temperatures of the bean.

There's fairly cheap one's available online.

Has anyone tried it? Especially with the Behmor.
Just wondering if it's worth trying. Visibility is limited in a behmor and the reflective parts as well as infrared/quarts lighting might throw off the temp reading completely.

I'm hoping it might at least give an semi accurate representation of the beans temps.


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Postby Burner0000 » Aug 25, 2012, 8:52 am

I have just been using a regular K-type thermometer. I can only get roast chamber temp so I use it to monitor cool down. To get the roast I want I just listen for cracks. It's old school but I get the roasts I want. I think if you use infrared and you can place the laser correctly then it should work. I have read a few threads about people doing so.

For City I hit cool during 1C
City plus I wait for 1C to end.
FC hit cool once I hear the first 2C
FC+ a few 2C's

Vienna roasts or darker I haven't tried but I believe if you wanna go that dark your burning off any tastes you would achieve from any profile.
Roast it, Grind it, Brew it!.. Enjoy it!..

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Postby berkinet » Aug 25, 2012, 12:10 pm

Infrared thermometers tend to not be all that accurate (often plus/minus 5 degrees Celsius), especially the inexpensive ones. They are fine for checking for relative change, and things like wood burning ovens where "close" is good enough. Depending on your needs, that might, or might not, be ok for coffee roasting.

Also, accuracy is a function of distance. The measured area expands as it gets farther from the sensor. So, if you are sufficiently far away, you might be measuring more area than you think.

Finally, the laser is just a pointer so you can see where you are aiming. It has nothing to do with the actual temperature measurement.

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Postby cannonfodder » Aug 25, 2012, 10:08 pm

They are not very good. If you are working though glass or trying to measure on a reflective surface like stainless steel your reading will be all over the place. There is also an issue of acclimating the thermometer to the environment. When I worked for a shipping company we were looking at using the expensive version to get spot readings on frozen goods. Problem there, you had to acclimate the thermometer in the environment you were using it. So to get accurate readings, it would have to sit in a -5 freezer truck for nearly a half hour before it would read accurately, if I remember correctly. You would be better off using an inexpensive K thermocouple.
Dave Stephens

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Postby Benjammer » Aug 26, 2012, 2:47 am

Thanks guys, I already purchased one because I was impatient and I figured it would be a cool toy to play around with either way. I'll let you know if it works ok for coffee roasting.