This tutorial presents extreme value theory (EVT) as an analytical tool in process characterization and shows its potential to describe production performance, eg, across different factories, via reliable estimates of the frequency and scale of extreme events. Two alternative EVT methods are discussed: point over threshold and block maxima. We illustrate the theoretical framework for EVT by process data from two different examples from the food-processing industry. Finally, we discuss limitations, decisions, and possibilities when applying EVT for process data.