Coffee | One Roast at a Time

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  • One | Roast at a Time | Roasts 51–66 – Multi-Coffee Validation

    Overview This set of roasts spans four different coffees and three processing styles: washed, natural, and wet hulled. The purpose was not to refine one coffee in isolation, but to observe how the Gene Café CBR-301 behaves across different coffees while holding the overall approach steady. Across the set, the machine remained consistent. The coffees…

  • A Note on Consistency and Control

    Most home roasting advice talks about control as if it’s something you can dial in from the first roast. In practice, it doesn’t quite work like that. What’s becoming clearer over repeated roasts on the Gene Café is that the machine behaves differently depending on its thermal state. A completely cold start often feels less…

  • Why I Don’t Use a Bean Temperature Probe on the Gene Café (For Now)

    One of the most common questions that comes up when roasting coffee is simple: What is the bean temperature? On most commercial drum roasters, that number is central to how the roast is monitored and controlled. A probe sits inside the bean mass and provides a temperature reading that helps guide drying, Maillard development, and…

  • Roast 50 — Colombia Supremo (Washed)

    Batch:250 g | 250 °C | Cold Start TRT: 13:21 | Weight Loss: 16.0% This roast marks the first Colombia Supremo roast in the project and serves as the baseline reference for the upcoming weekend series. The roast followed a stable thermal progression, reaching 200 °C at 4:19 and transitioning airflow to fan level 3…

  • Observation: Airflow Behaviour Around ~200 °C on the Gene Café CBR-301

    Context Over time, a recurring observation during roasting on the Gene Café CBR-301 began to stand out. Across many roasts, the machine appeared to change behaviour around the same point in the roast. The airflow seemed to increase, the roast environment stabilised, and the rate of temperature rise often became more predictable. At first this…

  • Roast #49 – Honduras Pacas (Washed)

    Finca El Paraíso — Santa Barbara, HondurasProducer: Wil Edilberto ArmijoVariety: Pacas (Bourbon mutation)Altitude: 1550 m This roast was intended as a personal roast for drinking, but also provided another opportunity to observe how the Gene Café behaves when using TRT as a guardrail. The roast followed a very typical progression for the machine early on.…

  • Roast 48 – Colombia SWP Decaf (Swiss Water Process) | Personal Roast

    This roast was carried out as a simple personal roast intended for home espresso. The coffee was a Colombia Swiss Water Process (SWP) decaf, and the roast began from a cold machine. Decaffeinated coffees often behave slightly differently during roasting. They tend to absorb heat more readily, produce a quieter or less distinct first crack,…

  • Roast 47 – Ethiopia Karume (Natural)

    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…

  • Roast 46 – Brazil Topazio (Natural)

    Cold Start Personal Roast This roast was carried out as a simple personal roast for home consumption. The goal was not experimentation, but to produce a comfortable everyday roast for espresso and milk drinks. Even so, it still provides a useful data point within the broader roasting project because the machine was started from a…