Second crack

The second crack is a stage in the process of roasting coffee beans, occurring at higher temperatures, typically around 220°C (430°F). It's characterized by a distinct cracking sound due to the internal expansion and breakage of the beans' cellular structure. This phase signals a deeper level of roast, where the beans develop richer, darker flavors and oils begin to emerge. In practical terms, it indicates the transition from a City or Full City roast to a darker roast like French or Espresso. The second crack helps roasters determine when to stop roasting to achieve desired flavor profiles.