What a Roasting Day Actually Looks Like
Green coffee in, roasted coffee out, and the several hours of unglamorous decisions in between.
Roasting looks like a craft from the outside and mostly feels like process control from the inside.
Before anything is hot
The first decision is which lots to run and in what order. This isn’t arbitrary. The drum carries heat between batches, so you sequence from lighter profiles up to darker ones rather than trying to drag temperature back down mid-session.
Then the green gets checked. Moisture content should sit around 10–12%; anything higher and the drying phase needs extending or the batch will finish uneven. Density matters too, because dense high-grown coffee absorbs heat differently from softer lowland beans, and the same profile applied to both produces two different results.
The Aricha lot is about as dense as anything we run. The Peru is noticeably softer. They do not get the same charge temperature.
The first batch is the odd one
The first batch of any session behaves differently from every batch after it, because the drum and the machine’s thermal mass haven’t settled. Roasters handle this in various ways, and whatever you do about it, the first curve of the day is the one to read most carefully. It’s the likeliest source of a bag that doesn’t match its siblings.
Steering the middle
Once the batch is in, the job is watching the rate of rise (how fast bean temperature is climbing) and keeping its decline smooth. Not flat, and not climbing. Steadily declining.
What you’re avoiding is a crash and flick: rate of rise falling off sharply, usually right after first crack when the bean turns exothermic and starts producing its own heat, then rebounding upward when you overcorrect. The resulting cup tastes baked and hollow in a way that’s hard to describe and easy to recognise once you’ve done it a few times.
Our standard shape runs 14–17 minutes with yellowing around the 7 to 8 minute mark and first crack near 199 °C. Development after first crack lands at about 20% of total time. The Roasting page has the curves and the full numbers.
Senses, still
Instrumentation tells you temperature and rate of change. It does not tell you when first crack has started, and it doesn’t tell you when a batch is going wrong.
- Sound. First crack is sharp and irregular, like popcorn. Second crack is quieter and faster, more like cereal in milk.
- Smell. Grassy, then bready, then toasty, then sweet and caramel-like. When it turns smoky you’ve gone past where we ever want to be.
- Colour. Least reliable of the three, but the shift from green to straw yellow is a clean marker for the end of drying.
The logger and the senses disagree occasionally. The senses win.
Afterwards
Coffee goes into a cooling tray immediately. Residual heat keeps roasting it otherwise. Chaff gets collected and composted, which is the only sustainable thing about the operation, and it’s a small one.
Then it rests. Fresh coffee is saturated with CO₂ and won’t brew properly for at least a day; espresso needs longer still, often three or four days before shots stabilise. Nothing gets cupped or shipped before it’s had that time.
Cupping, and being wrong
Every lot gets cupped after resting: dry fragrance, wet aroma, the crust broken at four minutes, then tasted repeatedly as it cools. Flavours that hide at high temperature show up as the cup drops, which is why the protocol is slow.
This is where profiles get corrected. If a batch comes through sour and hay-like, development was too short. If origin character has flattened into generic roastiness, it ran too long. Both happen. The point of logging every batch is that when something’s wrong there’s a curve to look at rather than a guess to make.
If you roast and want to compare notes, get in touch .