Rate of Rise (RoR)
Rate of Rise (RoR) refers to the rate at which coffee bean temperature increases during roasting, typically measured over 30–60 seconds. It is a crucial metric that indicates how well beans absorb heat during roasting.
A stable, low RoR benefits denser beans, allowing flavors to fully develop. Conversely, a high RoR toward the end of roasting can cause excessive heat absorption, leading to scorched or harsh flavors.
There are three critical RoR points in the roasting process: Maximum RoR, which occurs right after the turning point; First Crack RoR, when the beans first crack; and End RoR, which influences the final cup quality.