Today I did 550 Gr with my Turbo beast, and it went fine.
Got to full city + in 13 Minutes with slight profiling, and then took
two minutes to cool to 180 with the hair drier.
Because I was net short of a pound, I roasted a 150 Gr batch right
With the smaller batch I could observe the differences in the roast.
It looks like we have to consider something I will call thermal inertia
of the beans, for lack of a better description.
I preheated the roaster to 480F and dumped in the 150 Gr. The temp only
dropped to 350, and quickly rose up to 420. In about a minute.
No first crack!
So I held the temp in the early 420's as well as I could by turning the
thermostat on and off.
It took another good minute for the beans to get up to that temp and
finally get into first crack.
In almost 4 minutes first crack was boiling, still holding the temp
about the same.
At this point I started to ramp up slowly, and at 445 roaster temp I
held back again, and waited for the beans to catch up.
It took another 30 seconds before they started to crack in second.
The batch was finished roasting in about 7 minutes, and it took less
than a minute to cool it to less than 170F. Was not paying attention to
the cooling, but dodging chaff ;-) .
Another very even batch, matched the first, larger batch, perfectly in
So, with the same power, it takes longer to cook more beans :-) .
Not sure how all this applies.
Still leaning to roast after more than a year, here in LHC.