[Homeroast] Drum rotation > Jimma > PID iRoast

raymanowen at gmail.com raymanowen at gmail.com
Mon Oct 4 00:16:04 CDT 2010

No bean mass monitoring?

I've been wondering how to fabricate and install a thermal measuring device
that would Not be affected by the passing hot air that got the little orbs
hot in the first place. Wouldn't they be on the median between the incoming
air and exhaust air temperatures? Something is exactly that hot- I say it's
the beans.

You could be in the market for one of the channel amplifiers of a Leeds &
Northrup multi-point, multi-source chart recorder that plots individual
temperatures, the mode, the median and the mean traces. Relax, it's just
middle-school math. No me but all three kids did it.

Maybe you could find all this stuff on the 'Bay, but all the tubes will be
missing. No such thing as industrial or special purpose tubes or the gas
diodes in the current rare stocks, so Viel Glück.

One more little thing to consider- coffee beans are thermal conductors. The
heat you apply to the outside of a bean travels to the center of the bean
after a while. If the roasting profile is not too radical, the interior will
be roasted exactly the same as the exterior.

If you have to hurry the roast to avoid "baking" the beans, you'll have to
use some rapid temperature excursions to finish the profile trip. The
temperature gradient across the bean would yield an unintended (or not)
"melange" temperature distribution.

If your roaster has a "trier," what's the effect of the time delay of the
first beans into the cooler vs the last beans out the gate?

Cheers, Mabuhay, Prost auf dem besten schmeckenden Tasse Kaffee -RayO, aka
When seconds count, the cooler takes mere minutes.

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