I finally received some fine screen to use in place of the cloth vacuum filter that pretty much clogs up after each roast and has to be replaced with a clean 5" disc. OGH recommended 120 mesh, but could only find 100 mesh so used that. After two successive roasts this morning, it looks clean enough to go at least 5 or so before cleaning. Big improvement in air flow - Thanks OGH!
For some reason my line voltage at max power has dropped from 115VAC to 111, but at ~1600 watts, I'm still able to steer a 300 gm charge along a target profile for both what I prefer for pour-over / cone brewing and the somewhat darker roast my wife likes for her espresso. She prefers roasts that are just into 2C. In this system, in-chamber cooling is very rapid.
I've attached data log profiles for the two I did this morning along with photos that I hope will illustrate differences in color. I decided to throw in a Charbucks espresso roast shot for comparison. After trying Lavazza Super Crema and some previous roasts I did, she says she now notices the charcoal flavors in the Charbucks she'd been drinking for the past 10 years.
I've been getting up to right around 180°F on the blower motor outlet case temperature by the end of each roast running on 100% recirc, nowhere near the resettable thermal fuse or upper limit I set for the microprocessor to monitor. That whole component of the design turned out to have been unnecessary, but I guess it's better to be safe than sorry.
ChicagoJohn attached the following images:
Edited by ChicagoJohn on 04/18/2017 08:40
So many beans; so little time....