Diedrich IR-5 Analysis by Chris Kornman
Tasting Room Manager and self-avowed fan of slightly savory coffees Josh Wismans convinced the team this week to keep the Ngozi on our analysis schedule. Our initial sample roast showed off some conflicting flavor notes, but Josh really loved it and we decided to move forward with analysis.
I’m really glad we did, and I think after looking at the green and taking the coffee through a roast myself I understand why the sample roast seemed a little… complicated.
I ran a quick density and moisture reading on the Sinar before roasting, and was surprised at the low density reading. I figured maybe it was an error so I re-measured manually in the graduated cylinder, and indeed the coffee, contrary to regional norms, is surprisingly soft.
I’d been planning to roast this like a Kenya with a lot of heat, and I immediately adjusted my strategy based on the green reading to a lower charge temperature and a gradual ramp up in burner settings. I still wanted to run a fairly quick exit strategy from the drying phase, and with that in mind I did end up with an aggressive burner profile quickly as the turning point approached.
As anticipated, the coffee took the heat fairly quickly and reached color change at 4:30, not too bad for the combination of moderate charge temperature and brief soak. By five minutes into the roast I was coasting at idle burner setting and fully open airflow (though I did briefly revert to 50/50 just prior to first crack to avoid too much heat loss).
The coffee reached first crack a little earlier than expected, just a few degrees, and the low rate of rise after first crack kept the overall temperature quite low including final drop temp. Unconsciously, or maybe subconsciously, this had the effect of muting some of the inherently savory flavors and accenting a few of the more subtle floral, sweet herbal, and cola-like notes.
Interestingly, the low temperatures of the end roast still resulted in a relatively dark color score, which has been on-trend for basically all of our washed Burundi coffees this year, so keep a light touch on the flame as you sail into and past first crack, the reward will be a sweet and delicate, nuanced coffee without pretense.
