Every Thursday the unit gets loud. One twelve-kilo drum, gas fired, roughly nine batches, all logged in pencil on paper that gets increasingly covered in chaff by the end of the day.

We have tried software. It is genuinely useful for consistency and completely useless at telling you the beans smell wrong at minute eight. So the paper stays, and the software runs alongside it, one tracking the numbers, the other tracking the thing numbers can't catch.

By batch six or seven the log sheet is barely legible, smudged with pencil and dusted in chaff, and that's usually when the read on a roast gets sharpest, because by then your nose has recalibrated to the room.

Anything that misses the profile goes into the reject bin, which we weigh at the end of the month as a small act of accountability, mostly to ourselves, since nobody else is checking that number but us.