Context
Roast 34 marks two changes:
- New origin — Kenyan AA Natural (Wanted Coffee)
- New ventilation configuration — kitchen oven hood extractor replacing prior active exhaust setup
The extractor is not directly attached to the Gene Café exhaust.
It operates independently at full power during the roast, improving room air evacuation without mechanically pulling from the roaster.
This roast therefore serves as:
- A new bean baseline
- A ventilation change baseline
- A thermal stability check
Green Coffee Details
- Origin: Kenya
- Classification: AA
- Process: Natural
- Altitude: 1400–1800m
- SCA: 84.75
- Cupping Notes (supplier): Blackcurrant, Juicy, Lime, Butterscotch
Roast Parameters
- Roaster: Gene Café CBR-301
- Batch size: 250g
- Set temperature: 250°C
- Ambient temperature: 23°C
- No preheat
- Cooling initiated at: 13:00
Key Milestones
- 200°C reached at: 04:00
- 230°C reached at: 06:43
- Weight in: 250g
- Weight out: 209.5g
Calculated Weight Loss
16.2%
Observations During Roast
- Heat-up behaviour was stable and normal for a cold start.
- No unusual acceleration or delay through drying or Maillard.
- The oven hood ventilation did not appear to influence roast timing or heat behaviour.
- Colour at drop: uniform dull brown.
- No visible oiling.
- No patchiness or surface scorching observed.
Thermally, the machine behaved predictably despite the ventilation change.
Ventilation Change — System Reflection
Previous setup: active exhaust connected to roaster.
Current setup: oven hood extracting ambient air in roasting space.
Key takeaway:
The new ventilation improves air quality and smoke control without altering roaster thermodynamics.
Phase timings aligned with historical cold-start behaviour.
This is significant.
It suggests:
- Environmental stability has improved.
- Machine stability remains intact.
- Airflow variable has been simplified rather than complicated.
This change is likely beneficial long term.
Positioning the Roast
At 16.2% WL, this roast sits toward the upper end of my espresso preference range.
For this Kenyan natural, that likely means:
- Reduced lime brightness
- More rounded acidity
- Greater body
- Potential softening of fruit clarity
It is not a light, fruit-forward Kenyan profile.
It is an espresso-leaning Kenyan.
Intent
The plan was to target approximately 15.0–15.5% WL.
The 13:00 stop produced 16.2%.
This becomes a clean baseline under new ventilation.
No mid-roast adjustments were made.
Discipline was maintained.
Open Questions (to be answered in cup)
- Is acidity structured or muted?
- Does sweetness show clearly?
- Is there an earthy tone from roast level or origin?
- Does the profile suit espresso better than OXO Rapid Brewer?
Judgement deferred until rested and tasted.
What This Roast Represents
This is not a perfection roast.
It is a systems roast.
It confirms:
- The Gene Café remains thermally consistent.
- The new ventilation does not destabilise roast behaviour.
- 13:00 total time under cold start yields ~16.2% WL with this Kenyan natural.
That data point now exists.
And that is progress.