This was a surprise to me. I graphed the first 60 seconds of a roast from the CSV download file and found this. I thought maybe it’s an artifact having to do with an IBTS transition, but if I do the math from the IBTS Temp trace under the hump, I get about 244F/minute average RoR.
At first I thought that the beans surely get scorched by this, but I see no evidence of that. I guess the beans will absorb heat at whatever rate they can. Since the IBTS Temp trace rises quickly and then levels off, it looks like the beans actually can take in heat this fast.
By the way, 450g batch of high density beans, PH was 437F (225C), D7, F4. I’ve looked at some other roasts with variations in drum and fan and they look pretty much the same.
I wonder what’s happening within the bean that makes it resist heat again after about 20 seconds. I read some stuff about an evaporative front forming in the coffee beans that then resists the transfer of heat to the inner bean. Maybe this is evidence of that. Anybody got comments?
Cheers,
Jim