Inner & Outer Bean Temperature

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Postby unp77 » Fri Aug 07, 2015 7:58 am

Hello, here's a beginner question.
I've read that the result of a roasting process is affected by an appropiate progression between the inner & outer bean temperature, in order to make an intersection.
How the inner bean temperature is supposed to be measured? I guess the outer bean temperature is the one tested by the probe, but where does the inner temperature curve (shown in the profiles) come from?
Thank you!
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Postby N3Roaster » Fri Aug 07, 2015 9:09 am

With a fluid bed or oven roaster it's possible to embed tiny thermocouples in beans to measure internal temperature, but I don't know of a method for monitoring this during a roast that's practical. Unless you're reading a research paper that describes measuring internal temperatures in its methodology, any chart of temperature over time is approximate to the surface temperature (there's a little more going on there).

If you have a color/roast development meter/color tiles you can get some further insight by comparing how that reads with whole beans and how it reads with ground coffee or if you've got a good microscope you could crack open a bean and examine things like porosity. You could even pull samples throughout a roast to see how these are changing during the roast and compare that back to your roasting records.

That said, under and over development (and more) can also be tasted in the cup and you might find it more useful to try some different roasting variations and see how those taste.
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Postby unp77 » Fri Aug 07, 2015 3:34 pm

Ok, so i understand there isn't an established method...
Thank you Neil
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Postby AnandaKavanagh » Mon Aug 24, 2015 5:21 am

Cracking open/cutting a bean in half can also yield some insight - if the colour of the innermost part of the bean differs greatly from the outer layer you are likely roasting unevenly (varies depending on the bean and its density of course)
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