In coffee roasting, “first crack” refers to a significant stage in the roasting process when the coffee beans undergo a rapid expansion and produce a cracking sound. This occurs as the moisture inside the beans heats up and causes the beans to swell and eventually fracture.
WHEN DOES THE FIRST CRACK HAPPEN?
First crack typically happens at a temperature range of about 196°C to 205°C (around 385°F to 401°F). It signifies that the beans have reached a light roast level and are undergoing important chemical changes, including the caramelization of sugars and the development of flavors. Roasters often use the first crack as a cue to determine how dark they want to roast the beans, as the flavors and characteristics evolve significantly after this point.
WHAT HAPPENS AFTER THE FIRST CRACK?
After the first crack in coffee roasting, several important changes occur:
Flavor Development: The flavors continue to evolve as the beans caramelize further. This is where the complexity of the coffee profile increases, with more pronounced sweetness and acidity.
Second Crack: If the roast continues, the beans will eventually reach the second crack, which occurs at a higher temperature (around 224°C or 435°F). This cracking sound indicates that the beans are moving into a darker roast level, leading to more bitterness and a fuller body.
Oil Release: As the beans roast longer, oils begin to surface, especially in darker roasts. This can affect the flavor and texture of the coffee.
Color Change: The beans will darken progressively, moving from light brown to a darker shade, indicating the roast level.
Aroma Changes: The aroma of the roasting coffee will shift, with more robust, richer scents emerging as the roast continues.
Roasters often use the timing and characteristics of the first and second cracks to achieve the desired roast profile.