Gene Café CBR 301 300g Roast Test Went Wrong

I planned a 300g back-to-back roast consistency test on the Gene Café CBR-301. The idea was simple: three roasts, same coffee, same batch size, same machine. One cold start, two warm starts. I wanted to see whether I could manage three full-capacity Gene Café roasts close enough to each other to be useful. Then Roast 112 happened. This was a Central Kenya washed coffee, high altitude, with SL28, SL34, Ruiru 11 and Batian in the mix. The plan was to use Roast 112 as the cold-start anchor, then follow with two warm-start roasts. But the roast moved much faster than expected. The key checkpoints came early: 200°C at 4:10 230°C at 6:43 245°C at 8:20 First crack became clear around 10:16, so I shortened the roast heavily. Even then, the coffee finished at 18.8% weight loss, with uneven colour, heavy smoke, massive bean expansion and some very dark beans. Then a part came off the chamber: the CR73-005A blade cushion. At that point, the decision was simple. Stop the test. Do not run Roast 113. Do not run Roast 114. Inspect the machine, reset, and treat Roast 112 as a failed first attempt rather than a usable consistency anchor. This video is about what happened, why I stopped, and what this taught me about roasting 300g batches on the Gene Café CBR-301. It does not prove that 300g is impossible. It does not prove that the Gene Café cannot roast larger batches. But it does show why full-capacity roasting needs caution, especially with a high-altitude washed Kenyan coffee that moves faster than expected. Sometimes the plan is useful. Sometimes the data is useful. And sometimes the machine gets a vote. If you roast 300g batches on the Gene Café CBR-301, I’d love to hear how it behaves for you. Do you get even results? Do you shorten your roast times? Do you avoid 300g altogether? Or have you had a roast where the machine looked at your plan and laughed? Chapters: 00:00 Introduction — the 300g consistency test that changed 01:03 The original back-to-back roast plan 01:22 The Central Kenya coffee 01:49 Roast 112, 113 and 114 explained 02:28 The Gene Café app adds some drama 03:05 200°C at 4:10 — first warning sign 03:45 230°C at 6:43 — the roast is moving fast 04:27 245°C at 8:20 — the original plan is gone 04:37 Shortening the roast live 05:16 First crack around 10:16 05:50 The beans expand and smoke builds 06:43 Cooling the roast and weighing the result 07:03 18.8% weight loss 07:25 The blade cushion comes off 08:08 Why Roast 113 and 114 were cancelled 08:39 Stopping became the result 09:46 What I know versus what I think happened 10:52 What happens before trying 300g again 11:34 The real title of the video 12:15 Question for Gene Café CBR-301 owners