Warm Start Personal Roast
The second roast of the evening used Ethiopia Karume and was started shortly after the cooling cycle from Roast 46 had completed. The machine therefore began the roast in a warm state rather than from ambient temperature.
This roast again had a practical goal: producing coffee for home use rather than running a controlled experiment.
Nevertheless, the roast provides a useful comparison to the preceding roast because the starting thermal conditions were different.
Roast Details
Roaster: Gene Café CBR-301
Coffee: Ethiopia Karume (Natural process)
Batch weight: 250 g
Start state: Warm machine
Start temperature: 69 °C
Set temperature: 250 °C
Key Milestones
| Event | Time |
|---|---|
| 200 °C reached | 02:56 |
| 230 °C reached | 05:07 |
| Cooling initiated | 12:16 |
The roast progressed smoothly and followed a steady development curve without the need for manual adjustment.
No protection events occurred and the machine completed the roast without interruption.
Visual and Aromatic Observations
Colour development appeared slightly more rapid during the early portion of the roast compared with the previous batch.
At the end of the roast the beans displayed an even medium brown colour typical of a medium roast level. During cooling the aroma showed the characteristic fruit-forward notes commonly associated with Ethiopian natural coffees.
Expected Cup Profile
Based on the roast development and previous experience with this coffee, the expected profile should emphasise:
- fruit sweetness
- softer acidity
- medium body
- lingering finish
This roast should perform well as:
- espresso
- filter
- a brighter contrast to the Brazilian roast.
Observations From These Two Roasts
Although these roasts were carried out simply for home consumption, running them back-to-back still provides a useful observational comparison.
The most obvious difference was the starting condition of the machine.
The first roast began from a cold machine at approximately room temperature, while the second roast began shortly after cooling had finished, when the machine body and drum were still warm.
This difference in starting condition resulted in noticeably faster early temperature progression in the second roast.
The earlier temperature milestones were reached more quickly, while the overall roast length was slightly shorter.
Importantly, both roasts still completed within a very typical time window for this machine and batch size, and both produced visually even roasts.
Practical Takeaway
For everyday roasting, both cold and warm starts can produce stable and predictable results on the Gene Café CBR-301.
The main observable difference between the two conditions is the speed at which the early stages of the roast progress.
From a practical perspective this simply means that when roasting multiple batches in an evening, the second roast will often move through the early stages more quickly than the first.
As always, the final roast decision was based primarily on:
- bean colour
- aroma
- overall roast progression
rather than strictly on time alone.