by another_jim on Sat Jul 09, 2011 1:20 pm
I think we might be talking about two different things. This is my, admittedly 2nd hand, understanding
Using the heatgun with an open bowl and manually stirring is an artisanal method that takes about two years practice to get great roasts. The heatgun bread machine combo (HG/BM) is an improvement on the old turbooven/stircrazy design (SC/TO). The bread machine, like the old stir crazy, agitates the beans, the heat gun, like the old turbooven, supplies the convective heat.
The older SC/TO combination had two flaws: it was not well insulated, and the turboven used a click type thermostat with a huge deadband. Therefore, the roaster's ETs varied wildly over time and from center to edge, producing extremely dull roasts. The HG/BM system runs on a well insulated, higher thermal mass bread machine, while the heat gun's output is constant and manually adjustable. So the ET is constant across the machine and rock stable. With a well placed sensor for bean temperature, you can accurately set the heat gun and profile roasts precisely.
The drawback is that while assembling an SC/TO was idiot proof, one simply replaced the stir crazy lid with the turbooven lid, the HG/BM has to have the heatgun mounted and top sealed, as well as requiring a BT sensor for accurate roasts.
Since the knowledge required for assembly is higher, the people using HG/BM systems probably know more about roasting as well. This probably is an added reason for their good results.