The First Crack Only a Mentor Could Name

In a small roastery in Portland, Oregon, twenty-three-year-old Mateo Reyes stood over a drum roaster for the first time, overwhelmed by heat and noise. His mentor, a sixty-year-old Guatemalan roaster named Don Julio, had told him to listen for "first crack" — the precise moment the beans pop and release their deepest flavor. The first time it happened, Mateo thought it was the gas burner clicking.…