Thanks Dave, in response to your questions:
I use 250g weight
The chaff collector is the standard large one
I recently cleaned the chaff collector, but just used water, so definitely didn’t get everything out of it.
The ducting I use is 2m at its max. I understand anything longer leads to problems due to the fan on the machine not being strong enough. Therefore affecting air flow.
The model is second hand, but from 2021 according to the label.
That’s interesting about the the temperature gradient, I hadn’t considered the need to limit the ror early on.
As many have now said, it’s clear that this machine beyond many others requires roasting by feel, given the stats provided don’t provide as much insight as one might want. Having said that, managing to roast by feel takes time so having some signposts for newbies is helpful. Given the variability in all measures I suppose the most consistent signpost is likely to be time in each stage of the roast?
If so, here are a few generalities I’ve collected so far, as well as taking advice from this thread. Disagree if any of this is wrong and to emphasise, these are ball parks that will change significantly depending on the bean or if you are trying something beyond the basics.
- Keep full roast times between 11-15 minutes
- At warmish ambient temperatures, don’t use max wattage at any point.
- E stopping can damage the heating element.
- The cool down cycle is sufficiently fast to not impact flavour significantly.
Phases for a medium roast
- Drying phase - 40-60%, too long leads to baking? Ensure not max temp to avoid scorching later on.
- Maillard phase - 20-30% - longer for more perceived sweetness(?)
- Development phase (post 1c) 10-30% - longer creates more traditional coffee flavours, but reduces some of the single origin flavours. Longer also increases funkiness in more processed coffees.
