How coffee roasting works, one bean at a time

July 3, 2026 #coffee#roasting#interactive#explainer

I roast coffee at home under the name Hirsch Roast, and roasting is one of those things that looks simple and turns out to be mostly chemistry you cannot see. So I wrote it down as an interactive explainer: How coffee roasting works.

It follows a single bean the whole way - from a red fruit on a mountainside, through processing and drying, into the roaster, and out the other end into the cup. Along the way it gets into the parts I find genuinely interesting: where flavor comes from, what first crack actually is, and how extraction pulls it all back out in the brew.

The explaining is carried by around 27 interactive figures you can drag and scrub, with the writing kept short so the renders do the work. Read it here: coffee.hirschmann.io.

It is one of a pair. The sibling article takes the machine apart instead: how an espresso machine works.

The format is inspired by Bartosz Ciechanowski - long scroll, draggable figures, prose pointing at the visuals. I built the figures with Fable (Claude, by Anthropic), which handled the slow work of turning the chemistry into something you can play with.