What is a roast log?

A roast log is a record of the key data points from each roasting session - capturing what happened during the roast so that results can be analysed, replicated, and improved over time. At its most basic, a roast log records green coffee details, batch size, machine settings, milestone temperatures and times, end temperature, and a brief tasting note. More detailed logs capture full roast curves, RoR at key points, and systematic cupping scores.

The roast log is the foundational tool for developing as a roaster. Without it, you're relying on memory to reproduce a roast that worked well or diagnose one that didn't. With it, you build a searchable archive of every roast you've done - correlated with cup results - that over time becomes an invaluable reference for understanding how your machine behaves with different coffees, batch sizes, and profiles.

Modern roasting software - RoasTime (Aillio), Cropster, Artisan, Typica - automates much of the data capture, generating roast curves and storing all parameters digitally. For home roasters without software, a simple spreadsheet or notebook achieves the same purpose. The habit of logging every roast, even briefly, is one of the highest-leverage practices available to a developing roaster. The roasters who improve fastest are almost universally the ones who log consistently and review their data.