Elevation and fire
How we roast
Pale green coffee spends about ten minutes over the fire before it finds its color. Elevation sets the starting line. The fire decides the color and the aroma.
In the drum now · roast log of Ethiopia Guji
199℃
After first crack
Cinnamon
Charge
191–212℃
We pour the green coffee into the preheated drum. The clock starts here.
Turning point
1:08–1:18 · 88–95℃
The cold beans pull the drum thermometer down, and this is where it starts to climb again. It tells us how fast the beans are taking heat.
Yellowing
3:55–4:40 · about 150℃
The beans give up moisture and move from straw to yellow. The grassy smell turns into the smell of baking bread.
First crack
8:00–8:40 · about 196℃
Steam and gas inside the bean break through with a small pop. We log the time of the first pop.
Drop
9:20–11:00 · 201–215℃
After first crack we roast light roasts a little over one more minute, medium-light roasts 1:45–1:50, and medium roasts a little over two minutes, then drop them onto the cooling tray.
Elevation sets the charge temperature
Coffee that ripens slowly in cool, high places grows dense, hard green beans. The harder the bean, the longer heat takes to reach its center, so we raise the charge temperature, the heat of the drum when the beans go in, to match the elevation.
Our rule starts at 190℃ and adds 2℃ for every 100 m above 1,100 m. So Brazil Cerrado, grown at 1,150 m, goes in at 191℃, and Ethiopia Guji, grown at 2,200 m, goes in at 212℃.
Some coffees do not follow the rule. Colombia Decaf, for example, was soaked and dried again when its caffeine was removed, so it takes heat quickly and starts at 200℃, lower than the 204℃ the rule points to. The two blends mix green coffees of different hardness in one batch, so we charge them a little lower than their average elevation suggests to keep the softer beans from scorching (Blend 55 at 195℃, Blend 79 at 207℃).
Elevation is only an easy scale for choosing a flavor. Higher does not mean better. Variety, processing, and roast level shape the cup too.
- Charge temperature
- 191–212℃
- Rule
- 190℃ + (elevation − 1,100 m) × 0.02
Elevation1,850 m
Charge temperature205℃
From charge to drop, five points
For every coffee we log the time and temperature at the five points below. The ranges come from the roast logs of the 13 coffees we sell now.
- Charge 191–212℃
- Turning point 1:08–1:18 · 88–95℃
- Yellowing 3:55–4:40 · about 150℃
- First crack 8:00–8:40 · about 196℃
- Drop 9:20–11:00 · 201–215℃
An example log from a fictional roastery.
Ethiopia Guji Origin: Ethiopia
- Elevation
- 2,200 m
- Charge
- 212℃
- Turning point
- 1:15 · 92℃
- Yellowing
- 4:16
- First crack
- 8:12
- Drop
- 204℃
- Total roast time
- 9:50
- Roast color
- 76
Roast color
Roast color is the lightness of the finished beans, written as a number from 0 to 100. Higher numbers are lighter, and lower numbers are darker.
The coffees we sell now sit between 55 (Blend 55) and 82 (Panama Boquete Geisha). Light roasts are 76–82, medium-light roasts 64–66, and medium roasts 55–57.
Every coffee color on this site is calculated from this number. The same value always gives the same color: Rwanda Nyamasheke and Blend 79, both at 79, share one color. The numbers in the two blend names are this value too.
Roast color
76
Light
Roast color values are examples from a fictional roastery, not readings from a measuring device.
- Geisha(Panama Boquete Geisha), roast color 82, elevation 1,700 m
- Sidra(Colombia Nariño Sidra), roast color 81, elevation 2,150 m
- Yirgacheffe(Ethiopia Yirgacheffe), roast color 80, elevation 2,050 m
- Nyamasheke(Rwanda Nyamasheke), roast color 79, elevation 1,950 m
- Blend 79(Blend 79), roast color 79, average elevation 1,980 m
- Nyeri(Kenya Nyeri), roast color 78, elevation 1,800 m
- Guji(Ethiopia Guji), roast color 76, elevation 2,200 m
- Tarrazú(Costa Rica Tarrazú), roast color 66, elevation 1,650 m
- Huila(Colombia Huila), roast color 65, elevation 1,850 m
- Huehuetenango(Guatemala Huehuetenango), roast color 64, elevation 1,750 m
- Decaf(Colombia Decaf), roast color 57, elevation 1,800 m
- Cerrado(Brazil Cerrado), roast color 56, elevation 1,150 m
- Blend 55(Blend 55), roast color 55, average elevation 1,430 m
First crack
After yellowing, the sugars and amino acids in the bean turn brown and build aroma. Meanwhile the steam and carbon dioxide trapped inside build pressure, until around 196℃ the cell walls split with a small pop.
At that moment the bean swells once, and the thin chaff on its surface comes loose and flies around the drum.
The short time between first crack and the drop decides the balance of acidity and sweetness. In our logs it runs from 1:15 (Panama Boquete Geisha, Rwanda Nyamasheke) to 2:30 (Colombia Decaf).
- Cerrado2:15Brazil Cerrado: first crack 8:35, total roast time 10:50, after first crack 2:15
- Blend 552:20Blend 55: first crack 8:40, total roast time 11:00, after first crack 2:20
- Tarrazú1:45Costa Rica Tarrazú: first crack 8:25, total roast time 10:10, after first crack 1:45
- Geisha1:15Panama Boquete Geisha: first crack 8:05, total roast time 9:20, after first crack 1:15
- Huehuetenango1:50Guatemala Huehuetenango: first crack 8:30, total roast time 10:20, after first crack 1:50
- Nyeri1:25Kenya Nyeri: first crack 8:10, total roast time 9:35, after first crack 1:25
- Decaf2:30Colombia Decaf: first crack 8:00, total roast time 10:30, after first crack 2:30
- Huila1:50Colombia Huila: first crack 8:35, total roast time 10:25, after first crack 1:50
- Nyamasheke1:15Rwanda Nyamasheke: first crack 8:15, total roast time 9:30, after first crack 1:15
- Blend 791:25Blend 79: first crack 8:15, total roast time 9:40, after first crack 1:25
- Yirgacheffe1:20Ethiopia Yirgacheffe: first crack 8:20, total roast time 9:40, after first crack 1:20
- Sidra1:20Colombia Nariño Sidra: first crack 8:25, total roast time 9:45, after first crack 1:20
- Guji1:38Ethiopia Guji: first crack 8:12, total roast time 9:50, after first crack 1:38
We cool the beans right after the drop
Coffee out of the drum keeps cooking in its own heat. So the moment it lands on the cooling tray, arms sweep through the beans in circles while air carries the heat away.
We bag the cooled coffee within a day, write the roast date on each bag, and ship it the next day.
One drum roaster, one sample roaster
Every coffee we sell is roasted on a single 15 kg drum roaster every Monday and Thursday. New green coffees are roasted first on a 1 kg sample roaster, and we decide after tasting.
Each coffee page shows that coffee’s roast log as a curve. When we adjust the heat for the next batch of the same coffee, this log is our reference.
- One 15 kg drum roasterEvery coffee we sell
- One 1 kg sample roasterTest roasts of new green coffee and cupping