Coffee | One Roast at a Time

  • System Reflection — Thermal Memory on the Gene Café CBR-301 Is Not Subtle

    Roasts 32 and 33 were designed as a controlled comparison on the Gene Café CBR-301. Cold start versus warm start.Same Brazil Santos coffee. Same 250g batch size. Same 250°C set temperature. Same airflow pattern.The only meaningful variable was machine starting temperature. On paper, that felt minor. In practice, it wasn’t. Roast 32 began at room…

  • Cold vs Warm Start | TRT Discipline | Upper Guardrail Defined

    Roast 32 & Roast 33 — Brazil SantosThese two roasts were deliberately paired. The intention was simple:Test repeatability using Total Roast Time (TRT) as the primary control variable, while acknowledging machine thermal state. What followed was more instructive than expected. Context Same coffee.Same batch size: 250g.Same set temperature: 250°C.Same airflow behaviour (fan stepping to 3…

  • Gene Café CBR-301 — What I Wish I Knew Before Roast 1

    This sheet covers: Download: Gene Café CBR-301 — What I Wish I Knew Before Roast 1 A practical technical reference sheet for new Gene Café CBR-301 users. This free PDF covers safe starting points, airflow awareness, total roast time (TRT), weight loss guidance, and common early mistakes to avoid. Designed to help beginners roast more…

  • Brazil Santos Natural — Gene Café CBR-301 Sequential Heat Saturation Session

    250 g batches | 250°C set | 4 consecutive roasts Objective To test: This was a system experiment, not a flavour experiment. All roasts were Brazil Santos Natural, 250 g input, target temperature 250°C. Cooling cycles were allowed to complete to 60°C between batches in line with manufacturer expectations. Measured Data Summary Roast Start Temp…

  • Brazil Santos Natural | 250g → 207.4g (17.0% WL) | TRT Validation (Airflow Inflection)

    Context Roast 27 was designed as a TRT (Total Roast Time) validation test. The working assumption was: Cooling at ~13:30 should consistently land near ~16% weight loss. Roast 26 had previously landed at 16.2% using a 13:30 hard stop. Roast 27 was intended to confirm whether TRT alone is a reliable operational control. Parameters No…

  • Roast 26 – Brazil Santos (Natural) | TRT Push Upper Boundary

    Date: 22-Feb-2026Roaster: Gene Café CBR-301Batch: 250 gOut: 209.4 gWeight Loss: 16.2%Set Temperature: 250°C (initially 248°C, corrected at ~3:00)Total Time: 13:30 (cool initiated at ~13:31 logged)Fan: OFF → 2 at start; 2 → 3 at 04:21 (overheat event); fan remained at 3Stir: 2 throughout; stepped to 3 at endCrack Flag: Not recorded Intent This roast was…

  • Note – Roast 25 | When Time Wasn’t Enough

    Roast 25 was meant to be simple. Brazil Topazio.250g.250°C set.No mid-roast adjustments. The only deliberate change was the stopping logic: a fixed cool at 13:03. No chasing weight loss. No reacting to crack sound. Just a hard time stop. On paper, it felt clean. Controlled. Almost disciplined. The roast looked darker than expected. There was…

  • Note – On Repeatability, Correlation, and the Urge to Overcomplicate

    There’s a moment in this process where curiosity quietly turns into doubt. After consolidating the roast data into a single CSV and looking at correlations between weight loss, peak temperature, and total roast time, something just didnt land wit me. The relationships weren’t clean. Peak temperature didn’t predict weight loss. Total time didn’t tightly predict…

  • Resources

  • 2026