First Crack And Second Crack Explained

Roasters listen for two audible moments that mark the progress of a roast. First crack sounds like popcorn popping, and it signals the bean’s sugars beginning to caramelize.

First crack happens around 196 degrees Celsius, when moisture inside the bean turns to steam and bursts the cell walls. The roast is considered light to medium at this exact point.

Second crack, around 224 degrees Celsius, is quieter and faster, a crackling like Rice Krispies. By now oils reach the surface and the roast turns dark, past most specialty standards.

Most specialty coffee is dropped somewhere between first and second crack, which preserves the origin’s brightness and complexity. Going past second crack roasts away much of what made the bean special.

The cracks are more reliable than any thermometer because they report what is happening inside the bean, not just in the roaster. Experienced roasters time everything around them.

Learn to hear the difference and you can roast by ear. First crack says the coffee is ready, second crack says it is heading into dark, and the gap between them is where flavor lives.