Not the exact results you might be expecting, but a fun video in experimentation nonetheless – watch:
Tije wondered if it would be possible or even easy to roast with sunlight and a magnifying glass. As a boy he was successful at setting stuff on fire with his magnifying glass, so there might be enough solar energy to collect in a metal, reflective bowl catching the full blast of solar heat on a handful of coffee beans. Add a little shaking device and anyone can roast their beans on a sunny day. It’s grean, sustainable, fun and all. Tije made some tools and came over to try this together with Jan van der Weel and me. We’d like to say that the first results are simply astounding, but alas, they are not. A sunny afternoon went up in smoke. Very little smoke. But we had a great time.