Diedrich IR-5 Analysis by Chris Kornman & Doris Garrido
Having successfully dialed a recent Gesha from Guatemala on our Diedrich roaster, including a fun run as our light roast batch brew in the Tasting Room, I handed Production Assistant Doris Garrido the green and asked her to work with the existing roast recipe, noting anything that came up in the roast of this similar bean from Panama.
The profile draws on my years of experience working with nerve-rackingly expensive coffees in tiny quantities in the pre-2010 era, when the cultivar was still new on the scene to most roasters. Observing trends as we put small batches through trial and production roasts on a vintage cast-iron machine, the team I worked with and I began to develop a plan for this unique and special coffee type.
The cultivar has a tendency to scorch if exposed to elevated temperatures early in the roast, so taking a gentle approach early in the profile is preferable. As a result, or perhaps in combination with other physical metrics like moisture and density, the coffee will seem to resist heat during early Maillard stage. The roast is going to feel sluggish at first, yet in truth the coffee is going to run away from you if you press it too hard. Trust your instincts and keep Maillard on pace for at least 30% of your total roast time. You’ll need to actively manage your heat at the end of the profile, anticipating first crack and letting the beans develop color with a low rate of rise, between 10-15 degrees per minute once crack begins, decreasing towards the end of roast.
The 5.5 lb profile Doris executed expertly here starts with a moderate charge temperature and stable environment. The burners are at 30%, our lowest setting, with a 50% airflow baffle – this is roughly the machine’s idle setting. A full two minutes into the roast, at the turnaround, is where you should start to think about heat adjustments. Doris kicked up the burners to 70%.
Color change in the profile came late, at about five-and-a-half minutes, and here’s where Doris opened up the airflow fully through the drum. She held the burners at 70% briefly before edging down the heat delta in anticipation of first crack. Here, Doris noted that the coffee is exceptionally and immediately responsive to heat and airflow adjustments in the Diedrich, a bit of a rarity as many coffees offer sluggish response to operator adjustments on this roaster.
Preferring a light roast on this cultivar to bring out the floral notes and highlight the inherent complexity, Doris effortlessly navigated the final roasting stages, spending around 80-90 seconds after first crack in a low heat environment, allowing the exhaust and bean temperature to align at precisely the moment she dropped the batch in the cooling tray.
The roast was picture perfect, and the cup was extravagent. Excessive floral notes like hibiscus, jasmine, and orange and lime blossom were evident in both fragrance and flavor, followed by idiosyncratic fruit flavors of peach, mild citrus, and a hint of candied ginger. Doris’s smile beamed across the cupping table at me, and we waxed poetic about the beans, the roast, and the brew.
What a damn coffee, a coffee dreamer’s coffee. Put a good plan in place, follow it, and trust your gut with this exceptional offering. Happy roasting!
