When roasting coffee beans, the temperature & time profile is one of the most critical factors that determines flavor, body, and aroma. The exact temperatures and times depend on roast level (light, medium, or dark) and equipment type (drum roaster, fluid bed, etc.) the beans, bean density, and batch size their processing, etc .
Assuming you’re using a drum roaster and aiming for a total roast time of about 9–12 minutes
(a common sweet spot for balanced flavor and good development control),
these are typical averages and should give you a solid baseline. :
☘️ 1. Drying Phase (Green → Yellow)
Time: ~4–6 minutes
Temperature range: ~150–170 °C (302–338 °F)
Goal: Reduce bean moisture (usually ~10–12% down to ~2%).
Cues: Color shifts from green to pale yellow; hay or bread dough aroma develops.
Tips: Avoid heating too fast — scorching can occur if the drum is too hot early on.
🍞 2. Maillard Phase - Browning Phase (Yellow → Light Brown)
Time: ~3–4 minutes
Temperature range: ~170–200 °C (338–392 °F)
Goal: Caramelization, sugar browning, and Develop sweetness, body, and complexity.
Cues: Aroma shifts to sweet/caramel, Color changes to light brown.
Tips: This is the “flavor-building” phase. Control the rate of rise (RoR) carefully — steady but slowing.
Control here affects the eventual flavor depth and acidity balance.
🔊 3. First Crack (Development Begins)
Time of first crack start: ~7–9 minutes into the roast
Temperature: ~195–205 °C (383–401 °F)
Goal: Beans expand and release steam/CO₂; start of development stage.
Cues: Audible cracking (like popcorn); surface lightens slightly due to expansion.
Notes: This audible “crack” signals the start of development and the end of “drying.” Lighter roasts often end shortly after this point.
☕ 4. Development Phase (After First Crack → End of Roast)
| **Roast Level** | **Development Time** | **Typical End Temp** | **Notes** (after 1st crack)
| **Light Roast** | 30–90 seconds | 205–210 °C (401–410 °F) | Bright, acidic, origin- forward.
| **Medium Roast** | 1.5–2.5 minutes | 210–220 °C (410–428 °F) | Balanced flavor; sweet & round.
| **Medium-Dark Roast** | 2.5–3.5 minutes | 220–225 °C (428–437 °F) | More body and chocolate notes
| **Dark Roast** | 3–4 minutes | 225–235 °C (437–455 °F) | Begins around or after second crack; smoky, oily.
❄️ 5. Cooling Phase
Time: 2–4 minutes (rapid cooling is key)
Goal: Stop roast progression immediately to lock in the desired profile.
Tips: Air or drum cooling systems should drop bean temp below 50 °C (122 °F) within a few minutes.
⏱️ Typical Total Roast Duration
Roast Type Total Time
Light 8–10 minutes
Medium 10–12 minutes
Dark 12–14 minutes
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Here’s a typical medium roast curve for a Colombian washed arabica coffee (moderate density, ~10–11% moisture). Colombian beans generally do well with a balanced, steady heat ramp that brings out caramel sweetness, nutty tones, and a touch of fruit acidity.
☕ Medium Roast Profile — Colombian Coffee
Roaster type: Drum roaster
Batch size: Medium (e.g., 1–5 kg)
Total time: ~11 minutes
Target end temperature: ~218 °C (425 °F)
🔥 Temperature vs. Time Table
| **Phase** | **Time (min)** | **Bean Temp (°C)** | **Notes**
| **Charge** | 0:00 | **195 °C** | Add green beans. High enough to start drying without scorching.
| **Turning Point** | 1:30 | **~110 °C** | Bean temp drops as cold beans absorb heat.
| **Drying Phase** | 1:30–5:00 | 110 → 160 °C | Moisture loss; grassy smell fades.
| **Maillard Phase** | 5:00–8:00 | 160 → 195 °C | Caramelization begins; aroma becomes sweet/toasty. Rate of Rise (RoR) should slow slightly.
| **First Crack (Start of Development)** | 8:00–9:00 | **~200 °C** | Audible cracking starts. Keep airflow high to manage chaff and smoke.
| **Development Phase** | 9:00–11:00 | 200 → 218 °C | Balance caramelization and acidity. End around 2 minutes after first crack for medium roast.
| **Drop** | 11:00 | **218 °C** | End roast. Beans are medium-brown, matte (no oil).
| **Cooling** | 11:00–14:00 | Rapid cool to <50 °C | Stop development quickly.
📈 Roast Curve Overview
Imagine a smooth, slightly flattening curve:
Steep rise early on (0–4 min) → moisture evaporates quickly.
Gentle S-curve flattening (4–8 min) → Maillard reaction phase; color shift from yellow to brown.
Gradual taper after first crack (8–11 min) → RoR declines steadily until drop.
Approximate Rate of Rise (RoR):
Start: ~25 °C/min
Mid-roast: ~15 °C/min
End: ~5 °C/min
💡 Tuning Tips
If the cup tastes sour or sharp, extend Maillard by 30–45 seconds or slow the heat ramp slightly.
If the cup tastes flat or baked, increase heat earlier or shorten total roast time slightly.
For more sweetness, emphasize the Maillard phase (caramelization) by stretching 5:00–8:00 range.
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