Development contrast
Context
Roast 15 was planned as a controlled development contrast against Roast 14.
The intent was not exploration or optimisation, but to extend development slightly while keeping all other variables stable.
This roast exists to answer one question only:
Does slightly more development improve body and finish without muting clarity?
Roast details
- Input: 250 g
- Output: 213.4 g
- Weight loss: 14.6%
- Set temperature: 250 °C
- Total roast time: 12:55
- Cooling: Initiated immediately at end time
System behaviour
- Standard Gene Café airflow progression observed
- Fan increased from level 2 → level 3 at ~5 minutes (system-driven, expected)
- No manual airflow or drum speed changes
The roast followed a clean, uninterrupted baseline profile.
First crack
First crack was clearly audible and energetic, with sustained activity.
There was brief internal hesitation about pulling early due to:
- audible crack intensity
- perceived darkening inside the chamber
The roast was allowed to continue to the planned stop point based on time and intent, not crack behaviour.
Visual observations
- Beans appeared darker than expected while in motion
- Post-cooling colour resolved to an even, mid-brown
- No signs of scorching or uneven development observed
This reinforced prior experience that in-roaster colour perception under stress is unreliable.
Immediate interpretation
At 14.6% weight loss and 12:55 total time, Roast 15 landed squarely in the intended contrast band:
- clearly more developed than Roast 14
- well inside the established natural coffee guardrails
- no system anomalies influencing outcome
Crack audibility in this roast aligns with emerging understanding that crack behaviour on naturals is coffee-dependent rather than system-dependent, particularly once airflow behaviour is stable and repeatable.
What this roast contributes
Roast 15 confirms:
- Development level can be extended modestly without losing control
- Time and weight loss remain reliable anchors when crack is emotionally distracting
- Audible crack does not imply overdevelopment
- System predictability has reached a point where decision discipline matters more than signal chasing
This roast earns its place as a development contrast reference for Honduras Catuai naturals on this system.
Open follow-ups
- Tasting comparison vs Roast 14 (A/B)
- Structural differences: body, finish length, balance
- Whether this development level feels preferable or simply different
No conclusions drawn yet.