Sumatra from Aceh area isn’t that low grown generally (1250 to 1800 meters) but can be tough to roast. It often gets a heavy, dark roast treatment that obscures the coffee to a point. Lighter roasting is more challenging.
Air roasters do a pretty good job with this. It’s hard to scorch coffee in an air roaster … provided you don’t overload it.
Currently we use a 3 barrel Probat for samples but when I have a single sample to check out, I’m using Popper lately.
Here is a 1450 meter Sumatra from Aceh (near Lake Takengon) roasted for cupping in Popper.