I haven’t read much about when to adjust the power or the fan. Looking at some profiles, the fan is pretty static (maybe a single change) with multiple power adjustments. Other profiles, have pretty static power and multiple fan adjustments.
Heat can obviously decrease heat via decrease in power level, or increased airflow. Yet, it doesn’t seem apparent to me which is the best way to manage the heat in the chamber.
So a question for those of you who are more experienced, or have come up with a particular methodology, how do you primarily control your heat, and why have you chosen that (over alternative), and if you use both (fan/power level) why have you done that and how do you figure out which changes to make and when?
Personally, I try to keep things relatively simple, only switching from F2 > F3 (about half way through the roast) and modulating the P levels through out, decreasing and trying to end up at around P4 past FC.
I also like to minimize use of fan and modulate power to control the roast. Fan is easier to use because the curves respond quickly to fan changes. With 325g batch size, increasing fan to F4 or higher made the brewed coffee flat tasting (to me, anyway.). So I try to use just enough fan to clear most of the chaff.
With 500g roasts I’ve found that more fan is needed to clear the chaff with some beans. I’ve also gotten some smoky bitter flavors from dark roasts with fan only F3. So with those larger batches increasing fan to F4 or F5 to clear chaff and smoke seems necessary, usually late in the roast after FC.
Royal’s roasting notes for their Crown Jewels discuss how some beans need higher airflow. I don’t understand those ideas, but am suspicious that our machines behave differently than gas roasters in this regard. Maybe others can explain?
I used to use the fan as the primary control and it was hard to get consistent roast curves. I have since switched to only a few fan changes during a roast at the end to gently lower the ROR and clear chaff. I find I get better results this way.