I roasted up my first two batches last night. (Thanks again to Dave / Mill City for the sourcing the greens.)
I'm really pleased to be working with a washed Ethiopian coffee. They're my very favorites, low in supply at this time of year, and I struggle to retain their floral aromatics in my roasts. (Does anyone have suggestions for getting these aromatics to be prominent?)
I attempted to Marshall / Endlesscycles' suggestions. I'm using moderate airflow throughout dry and ramp (5 on an early fan Quest) and then maxing out in development, charging really hot (>480 F BT on my Quest), using a good bit of heat early, and hitting ~20% development time. (I shoot for 1:45 for my roaster.) I'm dropping these at 402-406 BT, which is a true city roast, with the last snaps of 1c occurring after drop.
Here we are...
Rao-sts 1-2, 3/9/2015, 12.27 & 12.53% WL respectively
Cupping, two-days post, 3/12 1:18, 1.3 TDS, 20% ext.
The first profile above was quite nice, sweet, tartaric acidity, a bit of jasmine (though it always shows up more on the cupping table than in brewed coffee, in my experience). The second was dramatically worse. There was a hollow, baked, and savory quality. I think there are two suspects - one, slightly flattened RoR ("plateauing RoR") and, two, an excessively long Maillard phase in an attempt to achieve declining RoR and possibly develop more florals.
V60, 3/14/2015, five days post.
I brewed up the first profile above. 1:16.5, 202 F, ~1.4 TDS, ~21% ext.
This was really nice - very sweet, with prominent tartaric and citric acidity. There was a bit of a bitter cacao finish and a mild astringency, which indicates to me that I went slightly overboard with the hot charge temp. I'll try 490 F MET rather than 500 F. The roast retained the florals. I brewed it for half a dozen people, all of whom enjoyed it. A friend of mine whose palate I trust referred to it as "explosively floral."
Two things I've learned that can inhibit florals in my Quest are excessive airflow and baking. I think I used to intuitively imagine that aggressive heat application would decrease florality, but that doesn't really seem to be the case. Rather, over-aggressive heat application early just resulted in a slight bitter edge.
I also roasted three more batches as an airflow experiment. Profiles were the same as above, but with different airflow so I won't post profiles. (I also accidentally overwrote the best one. Ugh.)
My Quest has the older style fan which allows lower airflow settings. I tried 3-3-max, 4-4-max, and 5-5-max for dry-ramp-development respectively. Although minor differences in development RoR wound up confounding the results a bit, I did find that 5-5-max traded off a bit of aroma intensity, especially florals, for a slight increase in sweetness. I preferred the slightly higher complexity and aroma of 4-4-max to the slightly higher sweetness of 5-5-max.
I remain unconvinced that flat RoR in dry or early-mid ramp (pre-caramelization) has any negative effect on cup quality.
Here I charged slightly cooler to avoid scorching (but still really hot), coasted a bit with the Quest's minimal thermal mass, moved into ramp pretty aggressively, but still long enough to generate aromatics, and dropped with 1:45 of development, 20% or just less than that. Moderate airflow through dry and ramp seems to offer the best results.
Airflow at 4 throughout dry and ramp, gradual increase to maximum, only maxing out at the end of development.
Same early airflow, faster maxing out of airflow in development. I am planning on implementing at least some airflow and amperage tracking for a better dataset.
Tasting, one day post, a few V60-02s 12:200 and 20:330, 201 F, 7.2 on the EK, with other palates
Tasted again three days post on a v60-01, 12:210, 201 F, 7.2 EK, 1.29 TDS, ~20.7% ext.
The first was cleaner, more honeyed, and more preferred. The second has a slight bitter, roasty edge. The flavors are relatively similar, but there's a chemical bitterness. Both are quite sweet. My best guess is that the slightly more aggressive MET charge in the second profile was at fault. Another hypothesis would be that the ramp got too hot, but that seems less likely as I've taken ramp up to 520 F before without any roastiness. Any other ideas?
Another profile, 3/20
I'm now using the events feature in Artisan, though events aren't always marked in 1c because there's a whole lot to think about.
From V60-02's 3/21, 201-202 F, 7.0 EK
Super sweet citrus, tropical fruit (mango), floral, milk chocolate
Thoughts from others - tangerine, strawberry, white grape, really sweet, one of my best roasts, etc.
I'm sipping on it right now as a 12:210, 204 F, 7.4 EK V60-01, and I think it's even better. Going a couple degrees hotter really brings out the sweetness even more.
Espresso, EK43, 1.4 grind, 18.3 dose in a VST 18, 56.8 g out, 22 sec. 200f. 7 bars.
crisp, sweet, super ripe; bright; insane condensed jasmine sweet tea florality; a really great shot
This roast was pretty spot-on. Next roast will be similar, but I'll try applying more early heat instead of in ramp and see what happens. I did achieve very good development with as much / more heat toward the middle of the roast.