Development (roasting phase)
Final roasting phase between the first crack and bean exit. Typically represents 20-25% of total roasting time (DTR). Determines sweetness, aromatic clarity and cup complexity.
Background & Context
The development phase is the final stage of the roasting process, beginning at first crack and ending at drop (when the roaster ejects the beans from the drum). During this phase, temperature continues to rise, Maillard reactions intensify, caramelisation proceeds, and the bean's structural cells expand as CO₂ is generated. The development time ratio (DTR) is the percentage of total roast time spent in the development phase — typically 20–25% for most specialty roast profiles, though modern light roasting experimentation has pushed DTR to 15% or lower. Too short a development time produces under-developed, 'grassy' or 'bready' cups — the bean's interior is not fully transformed. Too long produces baked, flat profiles where volatile aromatics are burned off. During development, the roaster uses temperature, airflow, and drum speed to shape the Rate of Rise (RoR): a controlled, gradual decline in RoR through development ensures even heat penetration without stalling. The development phase is where the roaster's craft is most visible — it requires active, real-time decisions in response to how the beans are behaving.
Practical Use
For home roasters using a drum or fluid bed roaster: monitor the time from first crack to drop. A 2-minute development time on a 10-minute roast (20% DTR) is a standard starting point. If your cup tastes grassy, underbaked, or lacks sweetness, extend development by 20–30 seconds on your next roast. If the cup is flat or biscuity (baked), try increasing airflow during development rather than extending time.
Related Terms
Related terms: First crack — marks the beginning of the development phase. DTR — the key metric for development phase control. Rate of Rise — the RoR curve during development defines roast quality. Baked roast — the defect caused by poor development management.