[Homeroast] Panama Carmen 7 Dias de la Bellota Help!
raymanowen at gmail.com
raymanowen at gmail.com
Thu Sep 16 12:05:01 CDT 2010
"the dT/dt across the individual bean and the peak temperature of the outer
and centerline of the bean." This will not be the same for every bean in a
roast, and I don't fancy it is for beans in my roast either. I do harbor the
sneaking suspicion that beans gain thermal energy through conduction,
convection and radiation.
The roasting drum is an outstanding example of beans' gaining heat via all
three modes. Due to the ultra short electromagnetic wavelength of Infra Red
radiation, it cannot penetrate the surface of the bean and depends on
thermal conductivity and cascading radiation to thoroughly heat the
succeeding layers of the bean after the first surfaces.
The first surfaces gain heat, by whatever method, es macht nichts how.
Afterward, all succeeding heat transfer to the cascading interior "surfaces"
after the first is the same. Microwaves are able to bake [ruin] and cook
[ruin] cakes and steaks from within because of the wavelengths of a few
inches generated by the cavity magnetron tubes.
Thermal Infra Red radiation is a longer wavelength, longer than visible
light. Around 0.1mm. Microwaves are about 100X the wavelength, so penetrate
and generate heat deeper.
Of course, the ways and means of accomplishing an apparent thermal profile
are different, and it is an inference that the observations represent the
actual internal temperature of the beans.
Post Hoc, ergo Propter Hoc- if you get the desired flavor from your machines
and methods, don't change a thing. Leave it to others to discuss the fact
that temperature measuring apparatus tells you its temperature. It's a leap
of faith to deduce that what you see is the bean temperature. It's not a
I-R devices are good, in that they read the radiation at the bean surface.
Beans are insulators, so the core could be lagging or leading the changing
surface temperature. You hold it steady? So do I- until I get to the last
step in roasting- cooling to stop the roast.
Cheers, Mabuhay, Lloniannau at fy ffrindiau coffi. RayO, aka Opa!
On Wed, Sep 15, 2010 at 9:15 AM, Allon Stern <allon at radioactive.org> wrote:
> On Sep 15, 2010, at 10:34 AM, Rich wrote:
> > It has to do with the dT/dt across the individual bean and the peak
> temperature of the outer and centerline of the bean.
> Exactly. And different roasters have different characteristics. It's
> perfectly valid to expect a roast to the same level from a Behmor and an
> iRoast to differ in some qualities.
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