[Homeroast] profiling (was Re: Two QM3 roasts of Limoncillo Pacamara DP)

Robert Yoder robotyonder at hotmail.com
Fri Jan 14 00:11:51 CST 2011

Hi Allon,
Are you talking about the Sivetz bump (hump)?  I see one of the Holy Grails as Bean Mass Temp, and this would certainly be an indicator.
I've been trying to get BMT readings, however tight their band, with the Behmor.  The QM3 may provide that opportunity.  
Happy Roasting,
robert yoder
> From: allon at radioactive.org
> Date: Fri, 14 Jan 2011 00:38:24 -0500
> To: homeroast at lists.sweetmariascoffee.com
> Subject: [Homeroast] profiling (was Re: Two QM3 roasts of Limoncillo Pacamara DP)
> On Jan 13, 2011, at 9:50 PM, sci wrote:
> > I'm trying to learn how to profile beans. 
> I had a thought about how to profile beans and I wanted to particularly get miKe's opinion on this....
> You can watch the heat, sure, but once a profile is set in the PID, it pretty much follows that profile, but I noticed something interesting when watching a PID roast of Jimma, using miKe's profile....
> with my PID unit, you can watch the % heat applied; it's interesting to watch the duty cycle of the heater at various stages in the roast. So when the roast hits a point that the beans are soaking it up, the heater works harder to hit a target temp, and when the beans are done soaking it up, the heater works less hard.
> I noticed that right at the end of the profile, it was just over a hump, as it were, the duty cycle went through a peak, and had just slacked off at the end of the roast, and that got me thinking, is this one indicator of a sweet spot?
> (not that all humps will indicate a sweet spot, but are all sweet spots right over a hump?)
> Should be educational to set a PID to a linear roast, then graph the % heat applied vs time, alongside the temp. I'm thinking that something like this might be a good calibration roast, which you could then use to determine where to start and end each stage's ramp, as well as EOR.
> Just a thought. Anyone?
> (wish I had a QM3 just so I could PID it :D )
> -
> allon
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