Coffee Roasting Temperature & Heat Management Guide
Target Temperature Milestones
Key Temperature Targets (Bean Temperature - BT)
- Charge: 135-140°C
- Turning Point: 105-110°C (at 90-120 seconds)
- Dry End: 150-155°C (at 3:30-4:00)
- First Crack Start: 165-170°C (at 6:30-7:00)
- Drop: 175-185°C (at 8:30-9:30)
Environmental Temperature (ET) Guidelines
- Charge: 95-105°C
- Turning Point: 90-100°C
- Dry End: 115-125°C
- First Crack: 125-135°C
- Drop: 135-145°C
Rate of Rise (RoR) Targets by Phase
Phase 1: Drying Phase (0-4:00)
Target RoR: 8-12°C/min declining to 6-8°C/min
- 0-1:30: 10-12°C/min (initial momentum)
- 1:30-3:00: 8-10°C/min (controlled decline)
- 3:00-4:00: 6-8°C/min (preparing for Maillard)
Phase 2: Maillard Phase (4:00-7:00)
Target RoR: 4-6°C/min
- 4:00-5:30: 5-6°C/min (flavor development)
- 5:30-7:00: 4-5°C/min (approaching first crack)
Phase 3: Development Phase (7:00-9:00)
Target RoR: 2-4°C/min
- 7:00-8:00: 3-4°C/min (early development)
- 8:00-9:00: 2-3°C/min (final development)
Heat Management Strategy
Pre-Charge Setup
- Preheat roaster to 200-220°C environmental temperature
- Set initial burner to 60-70% of maximum
- Airflow at 50-60% for small batch roasting
- Plan heat reduction schedule before charging
Heat Application Timeline
Phase 1: Drying (0-4:00)
Heat Management Goal: Controlled, declining energy input
0-0:30 (Charge to Turnaround)
- Burner: Start at 60-70%, immediately reduce to 50-60%
- Goal: Achieve turning point at 90-120 seconds
- Watch for: Rapid temperature drop, then gradual climb
0:30-2:00 (Post-Turnaround)
- Burner: Reduce to 40-50%
- Goal: Maintain 8-10°C/min RoR
- Adjustment: Small 5-10% changes every 30 seconds
2:00-4:00 (Late Drying)
- Burner: Gradual reduction to 30-40%
- Goal: Achieve 6-8°C/min RoR approaching dry end
- Critical: Don’t let RoR crash below 5°C/min
Phase 2: Maillard (4:00-7:00)
Heat Management Goal: Steady, controlled energy for flavor development
4:00-5:00 (Early Maillard)
- Burner: Maintain 30-40%
- Goal: Stabilize RoR at 5-6°C/min
- Watch for: Color changes, first aroma development
5:00-6:00 (Mid Maillard)
- Burner: Small reductions to 25-35%
- Goal: Maintain 4-5°C/min RoR
- Listen for: Beans expanding, subtle cracking sounds
6:00-7:00 (Pre-First Crack)
- Burner: Fine adjustments, possibly small increase
- Goal: 4-5°C/min RoR leading to first crack
- Strategy: Some roasters add 5-10% heat just before FC
Phase 3: Development (7:00-9:00)
Heat Management Goal: Controlled finish without stalling
7:00-7:30 (First Crack Peak)
- Burner: Reduce by 10-20% from previous setting
- Goal: Control the crack intensity
- Watch for: Even crack propagation through batch
7:30-8:30 (Mid Development)
- Burner: Maintain 20-30%
- Goal: 3-4°C/min RoR
- Strategy: Steady heat for even development
8:30-9:00 (Final Development)
- Burner: Final adjustments, possibly reduce to 15-25%
- Goal: 2-3°C/min RoR to drop
- Decision point: Monitor for desired roast level
Heat Adjustment Principles
When to Increase Heat
- RoR dropping below targets (especially <5°C/min in drying)
- Temperature stalling for more than 30 seconds
- First crack too quiet or uneven
- Bean development lagging behind time targets
When to Decrease Heat
- RoR exceeding targets (especially >12°C/min early)
- Temperature climbing too aggressively
- Environmental temperature spiking
- Approaching phase transitions
Size of Adjustments
- Large changes (15-25%): Only during major corrections
- Medium changes (10-15%): Phase transitions or significant course corrections
- Small changes (5-10%): Most common adjustments
- Micro adjustments (2-5%): Fine-tuning in development phase
Environmental Factors
Ambient Temperature Effects
- Cold days: May need 10-15% more heat throughout
- Hot days: Reduce initial heat by 10-15%
- Humidity: High humidity may require longer drying phase
Batch Size Adjustments
- Smaller batches: Reduce all heat settings by 15-20%
- Larger batches: Increase heat settings by 15-20%
- Different bean densities: Adjust initial heat ±10%
Troubleshooting Common Issues
RoR Too High Early
- Cause: Charge temperature too high or too much initial heat
- Fix: Reduce heat immediately, may need 20-30% reduction
- Prevention: Lower charge temperature for next roast
RoR Crashes Mid-Roast
- Cause: Too aggressive heat reduction
- Fix: Increase heat by 15-20%, then gradual reductions
- Prevention: Make smaller, more frequent adjustments
Stalled Development
- Cause: Insufficient heat in development phase
- Fix: Increase heat by 10-15%
- Prevention: Plan heat increases before first crack
Uneven First Crack
- Cause: Usually insufficient heat or poor heat distribution
- Fix: Small heat increase and ensure good airflow
- Prevention: Maintain 4-5°C/min RoR approaching FC
Advanced Techniques
Heat Soak Method
- Principle: Higher initial heat, then rapid reduction
- Timing: 70-80% initial, drop to 40% by 1:00
- Benefit: Better heat penetration, more even roasting
Gradual Decline Method
- Principle: Steady, predictable heat reductions
- Timing: Reduce by 5-10% every minute after turnaround
- Benefit: Very controlled, repeatable profiles
First Crack Power Method
- Principle: Small heat boost just before first crack
- Timing: Add 5-15% heat at 6:30, then reduce after crack starts
- Benefit: More explosive crack, better development
Remember: These are guidelines, not rigid rules. Your specific roaster, batch size, bean origin, and desired profile may require adjustments to these targets.