Roasting

Statistics

Consistency bands, area under the curve per phase, and the rate of rise slope from first crack to drop.

Three numbers that help you roast the same coffee the same way again: the area under the bean temperature curve (how much heat the beans saw), the slope of the rate of rise through development (whether RoR keeps falling or flicks up), and how far a set of roasts spread around their mean (how repeatable you are).

AUC (area under the curve)

BT summed over time, in °C·min. It tracks roast degree better than the drop temperature alone.

It runs from a landmark to DROP and counts only BT above a base. Set both under Settings → Roasting → Area under the curve (AUC): From CHARGE, turning point, dry end or first crack, and Base (0 counts everything). Many Artisan users start at the turning point.
Per phase: drying (CHARGE to dry end), Maillard (dry end to first crack) and development (first crack to DROP). With the start at CHARGE they add up to the total.
Live: on the Roast page's Phases tab, the roast's AUC so far, the profile's at the same roast time (amber when they differ by more than 5 % or 30 °C·min) and the profile's at its end as the target.
After the roast: History → the roast shows it with its phases; Compare roasts shows it side by side, with each roast's difference from the reference.

Each roast stores its AUC with the setting it was completed under. History, the roast report and Compare work it out again from the curve with the current setting.

RoR slope, first crack to drop

How fast the rate of rise falls through development, in °C/min per minute: a straight line fitted through RoR from first crack to 15 s before DROP (so the drop itself does not count). It needs first crack and DROP at least 45 s apart. Negative means RoR is falling, the usual aim; near zero or positive means a flick. It shows on the roast's page in History (RoR slope FC → drop), in its report, and in Compare roasts.

Consistency (Compare roasts)

In History tick the roasts to compare and press Compare:

Consistency band: draws the mean ± σ (standard deviation) of BT and of RoR across the roasts shown, every 5 s where two or more have data. Each roast counts from its CHARGE to its DROP, aligned as the page's Align on says.
BT spread: the band's σ averaged over the roast, and its largest value: one number for how repeatable the set is.
Mean ± σ row under the table: time, first crack, DTR, the RoR slope, drop temperature, AUC and weight loss.

From the command line, roast compare reads the same roasts against a reference (roast analysis).