What Is First Crack and Second Crack?

Question

Accepted Answer

At First Crack (196–205 °C) the bean pops audibly — similar to popcorn. Second Crack (224–228 °C) is quieter. Light roasts end after First Crack, dark roasts after Second. First Crack and Second Crack are acoustic markers that tell the roaster which phase the roast is in. They're so central that experienced roasters can track a roast's progress by sound alone — even without a thermometer. First Crack occurs at a bean temperature of roughly 196–205 °C. At this moment, the steam pressure inside the bean is so high that the cell structure gives way. Water and CO₂ escape suddenly, the bean nearly doubles in volume and becomes noticeably lighter. The sound resembles a soft cracking or crackling — comparable to popcorn. After First Crack, the development phase begins. This is where the roaster decides the coffee's character. The longer they roast past First Crack, the less acidity and the more roast flavours develop. Light roasts (the specialty standard for filter coffee) are finished a few seconds to one minute after First Crack. Second Crack occurs at approximately 224–228 °C. Now finer cell structures tear open, and oils emerge on the bean's surface — the bean becomes glossy. The sound is quieter and higher-pitched than First Crack, more of a fine crackling. Dark roasts (traditional Italian espresso) are finished after Second Crack. Roasting well beyond Second Crack burns the bean — ashy flavours and extreme bitterness are the result. At our café on Sophienstraße 27 in Berlin-Lichtenberg, we mainly serve light to medium roasted coffees. When guests ask why our espresso tastes "different" from the Italian place, I explain: the difference lies exactly between First and Second Crack — a few degrees and a few minutes that change everything. You'll find us at Sophienstraße 27 in Berlin-Lichtenberg, Monday to Friday 8am–5pm and Saturday 10am–5pm.

What Is First Crack and Second Crack?

Why that is

In practice at Green Wall Coffee

Further reading