How are the greens processed: natural, washed? Curious if the color variation in the roast color matches the color variation in the greens. I used to aspire to a uniform roast color, but then it occurred to me that the color variation could be better for blending the flavors of different roast levels. You've also vanquished my preconceptions about scorching with a pan roaster - you clearly got some skillz.

Your beans must have cooled a bit before transferring to the stovetop, given that it took (typically) two minutes to first crack. I get to first crack in about 30 seconds with my air roaster, with a total time in the high-heat phase of 2.5 minutes.

This is what the roast looks like green / just before jumping to high heat (approximate image taken from Sweetmaria's) / end of roast / three days later:



Tastes lighter than it looks. I too have been questing to boost the sugary notes to balance against my preference for darker roasts.

GDM528 wrote:How are the greens processed: natural, washed? Curious if the color variation in the roast color matches the color variation in the greens. I used to aspire to a uniform roast color, but then it occurred to me that the color variation could be better for blending the flavors of different roast levels. You've also vanquished my preconceptions about scorching with a pan roaster - you clearly got some skillz.

Your beans must have cooled a bit before transferring to the stovetop, given that it took (typically) two minutes to first crack. I get to first crack in about 30 seconds with my air roaster, with a total time in the high-heat phase of 2.5 minutes.

This is what the roast looks like green / just before jumping to high heat (approximate image taken from Sweetmaria's) / end of roast / three days later:

Tastes lighter than it looks. I too have been questing to boost the sugary notes to balance against my preference for darker roasts.

My concern with the oven method is that it is effectively creating a large RoR crash during transfer right before 1C then when the heat is reapplied the RoR spikes back up. Uncharted territory there. I can see the stove top method working more in-line with accepted BT profiling because the beans never leave the heating environment but it sounds like it stalls the roast then hits it with heat to push into 1C. Almost like an older-style S-curve espresso profile that lengthens Maillard before a gradual bump into 1C.

Milton, are you data logging with any type of temperature probe or going off of time and sensory information like first crack, smells, and color changes?

Sorry it didn't turn out better. Makes me appreciate the tiny batch size of my roaster (2 ounces) that limits the tragic losses in the name of science.

The low acidity of Batch 1 makes sense, given the 4 minutes it spent at high heat - that's long, even for a drum roaster. When I was experimenting with lower browning temperature/times, I also experienced grassy, organic notes that I'd rather not know about. It wasn't until I went above 175C before that went away.

Batch 2 is interesting, as it implies it takes time to cook out the grassy notes - that's inspired me to try longer browning times in my roasts. Also interesting that the acidity drops when raising the browning temp 20F.

Batch 4 took longer to reach first crack then to it did to finish, which seems counterintuitive. Perhaps because the heat level of the beans were more uniform. In my air roaster, first crack start to finish takes about 1:30

Batch 3 seems closest to 'the zone', but sadly no brown sugar notes. You mentioned they don't come out of the Dutch oven as dark as the image I posted - that may be a clue. I've been shooting for a dark caramel color just before hitting the high-heat levels. Furthermore, I worry the high heat is incinerating the caramelized sugars, so I haven't dared spend more than 2:30 there. But, (and this may be significant) I don't pause between browning and development as you do when transferring from Dutch oven to skillet. The specific heat capacity of a roasted coffee bean is pretty low, so even a few seconds at a lower temperature will significantly cool the beans.

Appreciate your experimentation! Even though we're using significantly different methods, you've given me some more ideas to try out.

I've observed that my 'stepped' roasts (similar to your experiments) can visually change pretty dramatically over the course of 1-2 weeks. Some roasts will go from medium-dark and dry, to dark and oily - a full roast level change. I'll pay more attention to the flavor changes, but it's hard to remember over the course of more than a week.

I let my coffee rest a week or so before brewing it for enjoyment for both espresso and drip. I don't say this as gospel, it works for me and my workflow. Espresso typically always needs at least a week to off gas but drip may be good after a few days. When I do a cupping of roasts that only set overnight I can nearly always expect some level of "harshness" that goes away after a few days. The hard part about roasting coffee is how long it takes to iterate: roast, then wait for it to off gas, then taste, and then make an adjustment. You can't rest on your laurels either. Greens go bad, the next harvest is different, and so goes the pursuit of exceptional coffee.