Roast formulas
Published because roasting is not a secret, it is a habit. Times are minutes from charge, temperatures are bean probe.
Measured on a 3 kg drum, 2.1 kg charge, ambient 18–22 °C. Development ratio is the share of total roast time after first crack.
| Coffee | Charge | Turning point | First crack | Drop | Total | Dev. ratio |
|---|---|---|---|---|---|---|
| Morning Blonde | 188 °C | 1:22 / 92 °C | 8:40 / 196 °C | 201 °C | 10:05 | 14 % |
| Nyeri Light | 190 °C | 1:18 / 94 °C | 8:55 / 197 °C | 203 °C | 10:30 | 15 % |
| Boquete No. 4 | 184 °C | 1:30 / 90 °C | 9:20 / 195 °C | 200 °C | 10:50 | 14 % |
| Quiet Hour | 195 °C | 1:15 / 96 °C | 8:10 / 198 °C | 208 °C | 10:20 | 21 % |
| Drumline | 198 °C | 1:10 / 98 °C | 7:55 / 199 °C | 212 °C | 10:40 | 26 % |
| Late Fire | 202 °C | 1:05 / 101 °C | 7:30 / 200 °C | 218 °C | 11:05 | 32 % |
The moment the bean mass stops losing heat to the drum and starts gaining. Earlier means a hotter charge; later usually means we overloaded the batch.
Below 15 % the cup stays bright and tea-like, which is what we want from the blonde roasts. Above 25 % the sugars take over and origin character fades.
These numbers belong to our drum and will not transfer directly to yours. Treat the shape as the instruction and the absolute temperatures as noise. Write to us if you want the full logs as CSV; we send them to anyone who asks.
Ask for the logs