... the placement of the t/c in the chamber is not as important as its consistent presence in that spot.. I think what milowebailey for got to say after he said he always roasts on (6) in his sonofresco is that then when he reaches the level of roast he wants he turns off the gas switch to stop the roast...
I've got a handful of 12" x .125" diameter, 'type T', s/s Omega probes. I'll rig up a way to suspend one through the flue so it'll be located in the same spot each time. Maybe the s/s sheathing and the ungrounded t/c will negate some of the YoYo effect?
I picked up the Dude's reasoning for using the #6 setting, and I've been doing the same since we discussed it in another thread. I call it City roast when I hear the outliers of 1st crack but before the first 2nd crack outliers. This works pretty well but I'm a control freak and using sound is a bit imprecise. That's why I'm obsessing about a more predictable way to measure bean temps.
Here's an observation: I roasted a Yirg Koke yesterday - the same one I've mentioned before that I had problems achieving an even color. That was using the UFO/CO.
With the Sonofresco I was wondering;
* Would the 1/4" beans reach temp more quickly than the 1/2" beans.
* Would the outliers be spread even more widely because of the variation in bean size?
Answer;
It didn't seem to matter. The outliers were no more noticeable with this batch than it was with a batch of Brazilian beans that were more carefully sized. So if bean size didn't exacerbate the outliers situation, why not? Are the smaller beans harder than the bigger beans, giving them the same mass as the larger beans? I might have to dig some of my fracture testers out of mothballs to see if there's a density thing going on here. Hmmmm
Bottom line: This yirg roasted nice & evenly to a light City roast by stopping the roast as the 1st crack outliers were sounding off. The cup of vac pot I had for my cafe au lait was very fragrant and clean tasting. The aftertaste was pleasant and long-lasting. According to my notes I like this bean roasted lighter, so next time I'm going to stop the roast just as the 1st crack starts to slow down.
I'm seeing some progress with the Sonofresco.
Thanks for your help!