Quarlow Roasting Co.
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Roasted beans dropping into the cooling tray of a drum roaster

Sheets 401 to 418

Every batch, written down while it was still hot.

The sheet hangs by the cooling tray and gets copied here on Friday. Nothing is tidied up afterwards — an early crack stays an early crack.

Batches, most recent first · times are minutes:seconds from charge
Sheet Day Lot Green Turn Crack Drop Dev DTR Loss
418 Gitwe 12.0 kg 1:42 8:36 10:22 · 204 °C 1:46 17.0 % 15.4 %
417 Cerro Azul 12.0 kg 1:48 8:54 11:02 · 208 °C 2:08 19.3 % 16.0 %
416 Karimikui 11.6 kg 1:38 8:20 10:05 · 203 °C 1:45 17.4 % 14.6 %
415 La Ilusión 12.0 kg 1:45 8:48 10:40 · 206 °C 1:52 17.5 % 15.1 %
414 Sítio Bela Vista 12.0 kg 1:52 9:06 11:28 · 211 °C 2:22 20.6 % 16.8 %
413 Alaka 11.0 kg 1:34 8:12 9:44 · 202 °C 1:32 15.8 % 14.1 %
412 Cerro Azul 12.0 kg 1:51 9:04 11:14 · 208 °C 2:10 19.3 % 15.8 %
411 Karimikui 12.0 kg 1:39 8:26 10:18 · 205 °C 1:52 18.1 % 15.0 %

Sheet 418 · Gitwe

First full batch of the new Rwandan. Held the gas down through the turning point because naturals scorch at the drum wall, and it still arrived at the crack eight seconds early. Sheet stands as the reference.

Sheet 417 · Cerro Azul

Third batch of the morning, so the drum was already hot and the turning point came six seconds sooner than on batch one. Air up a notch from the crack to keep the finish clean.

Sheet 416 · Karimikui

Short charge — the sack was down to its last 11.6 kg. A lighter load climbs faster, so the gas came off ten seconds earlier than the sheet says and the curve landed on top of the reference anyway.

Sheet 415 · La Ilusión

Reference roast. Nothing to report, which is the point of writing it down.

The null case · batch 000

Reference charge, gas off

Twelve kilos of Gitwe charged into a cold drum with the gas closed, dropped at the same 10:22. No crack, no development, development ratio 0.0 % end to end. We run it once a quarter to prove the sheet, and it is the control for the timeline above: scrub it from charge to drop and nothing changes, because the grade factor is exp(0) = 1 at every point.

Dark roasted coffee at drop, graded by a development ratio of 17 per cent
Sheet 418, drop Development ratio 17.0 % · graded to exp(−1.6 × 0.170) = 0.761 of the master's luminance
The same photograph shipped ungraded, as the control
Batch 000, gas off Development ratio 0.0 % · graded to exp(0) = 1.000, so this is the master, untouched

Same photograph, same box, one number apart. Everything on this site that carries a picture carries a development ratio with it, and Y_shipped / Y_master = exp(−1.6 × DTR) is checked against the shipped files by scripts/plates.mjs. Batch 000 is what the law looks like at zero, which is why the timeline's first four frames are untouched too.

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