Coffees for Roast Summit
This is supplementary information about the coffees that you’re tasting today. I hope this helps you understand more about how to shape the flavor of your coffees as you strive for continuous improvement.
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All of the roasts were done on a traditional drum-style roaster with propane gas.
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All batch sizes were 2 kg in a 3 kg-rated coffee roaster. The drum volume is ~ 13.5 L, and my batch size was representative of 22% of the overall drum volume (not counting space taken up by the mixing arms and drum axle).
- Rob Hoos
Coffee #1
This acclimatization roast is taken a little darker than I generally like to go, in order to bring everyone into a space for tasting dark-roasted coffees. It is meant to be a shock to the system.
Finca La Unica and Alejandra
Processing: Anaerobic Natural
Farmer: Leticia and Adelmo Lopez
Region: Corquin, Copan Honduras
Variety: Parainema, Lempira, Obata
Altitude: 1000 - 1400MASL
H2O%: 11.8%
Aw: 0.56
Water Displacement Density: 1212.7 g/L
Coffee #2
The second roast features a darkly roasted coffee with a consistent, moderate airflow. This is meant to be the baseline roast for how I would approach dark roasting a coffee. I will be using the same greens for the next few roasts, where I hold the profile as close to the same as possible while varying airflow and drum speed.
Finca La Unica
Processing: Washed
Farmer: Leticia Lopez
Region: Corquin, Copan Honduras
Variety: Parainema,
Altitude: 1400MASL
H2O%: 10.8%
Aw: 0.577
Water Displacement Density: 1210.7 g/L
Coffee #3
The third roast features a darkly roasted coffee with a consistent, high airflow. Hallmarks of the higher airflow approach would be the need for increased burner throughout the roast coupled with a significantly lower inlet air temperature.
Finca La Unica
Processing: Washed
Farmer: Leticia Lopez
Region: Corquin, Copan Honduras
Variety: Parainema,
Altitude: 1400MASL
H2O%: 10.8%
Aw: 0.577
Water Displacement Density: 1210.7 g/L
Airflow Comparison
Here in the comparison of the 64% airflow (I call moderate) and the 100% airflow (I refer to as high) you can see the pronounced differences in the burner adjustments as well as the inlet air temperature.
Coffee #4 Slower Drum
The same green coffee is used in the second and third roasts. Here, the drum speed was reduced from my usual maximum of 72 RPM to 60 RPM. This is a 3-kilo roaster with a drum diameter of 10.25 inches ~ 26 cm.
Finca La Unica
Processing: Washed
Farmer: Leticia Lopez
Region: Corquin, Copan Honduras
Variety: Parainema,
Altitude: 1400MASL
H2O%: 10.8%
Aw: 0.577
Water Displacement Density: 1210.7 g/L
Drum Speed Comparison
Here in the comparison of the 60 RPM and the 72 RPM drum speeds. These roasts couldn’t be a perfect match on the roast curve, sadly, because at 2kg in my 3kg roaster - without the additional loft of the coffee into the hot air moving through the drum - I couldn’t keep up. Dev time, end of roast temp, weight loss %, and color were all on target… just a slightly slower time to yellow and a little more harrowing approach into first crack.
Coffee #5 Lower Altitude
In this roast, I went with a different coffee that is extremely close to La Unica, but with a slightly lower growth altitude. Additionally, please note this isn’t a perfect 1:1 because there is the addition of some Lempira, and the moisture content is slightly higher. But it is close enough to give us a good comparison.
Finca Terrerito
Processing: Washed
Farmer: Adelmo Lopez
Region: Corquin, Copan Honduras
Variety: Parainema, Lempira
Altitude: 1000MASL
H2O%: 11.5%
Aw: 0.567
Water Displacement Density: 1195.3 g/L
High / Low Altitude Comparison
Here you’ll see the High Altitude Roast vs. the Low Altitude Roast. These coffees took to the heat quite differently from one another. That being said, we ended up with a great match to try and control extraneous variables and strive to taste the difference in growth altitude when it comes to sourcing coffees for Dark Roasting.
I went with a wildly different coffee for the final tasting. Mostly, I wanted to show how I would approach dark roasting a coffee that is completely different when it comes to cultivars and processing method.
What I thought I was roasting:
Sumatra Gayo - Wine Process
Processing: Anaerobic Natural “Wine Process”
Farmer: Smallholder Producers
Region: Aceh, Indonesia
Variety: Typica, Abyssinia, Catimor, P-88
Altitude: 1550 MASL
What I may have actually roasted:
Sumatra Gayo Anaerobic Natural - Triple Picked
Processing: Anaerobic Natural
Farmer: Smallholder Producers
Region: Aceh, Indonesia
Variety: Catimor, Timtim, Bourbon, Ateng Super, P-88
Altitude: 1550 MASL