TomC wrote:While it remains to be proven, I'm starting to think that I can also modify (slightly) how I begin the roasting process. Since the roaster is now obviously more capable in terms of convective heat transfer, I don't have to rely on conductive drying as much in the first phase. What I aim to accomplish is simply running the drying phase with just a tad less heat on the element, and just the slightest trickle of the fan. My personal opinion is that this might lead to better effects in regards to maillard reactions and the surface of the bean at the end of the roast. Theoretically, it might allow for better developed coffee at a lower finish temperature and surface color. But that remains to be seen.
I think the significant portion of conductive heat transfer with such a thin drum on these little roasters is not the most ideal setting.
This sounds interesting-- pretty much the opposite of what I've been up to.
I did make a mod similar to yours on the exhaust vents-- rather than cut them, I twisted them with pliers to flatten them all out. I can feel higher air flow.
I have been aggressive with heat based on a few heuristics (and have recently bumped air up to 5-6 since putting holes in the drum and opening the vent):
1. To have system energy for a declining ROR, charge hot (400F+)
2. To lengthen drying time (and change the curve shape) especially to tame naturals, cut power after charge and add power back after turning point
3. When ROR peaks after drying, start edging power off to prevent a ROR straightline bake
4. Approaching first crack back off power to prevent spike in ROR
5. Then reintroduce power to avoid a dip in ROR
6. Ride out ROR curve in downward slope adjusting power
7. When ROR has no room left in downward slope, drop
It always tastes sweet with a balance of acidity and no grass even if dropped as low as 381F. I do use the variety of drop temps in a series of batches to create roast blends which has been quite nice. This seems largely a factor of how far I let the ROR peak after drying before edging off power. That way I can get drop temps ranging say 390-415 then mix a light and a dark.
However, this is clearly not a great approach in terms of setting and meeting a drop temperature target. And florals and strong fruits are just teases now and then.
How does this relate to mods? Well, it relates to your point about agility of the roaster and how mods to the drum and vent allow for easier changes during the roast. Before I felt I had to build up a huge heat bank to coast me through a declining ROR, then I had to do that even more if I wanted to extend drying by cutting power from drop to turning point.
I guess I could use some improved heuristics as they relate to the mods. Particularly as I'd like to move to a TC4 setup this fall.