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.

What Is First Crack and Second Crack?

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.

Why that matters

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 Green Wall Coffee

At our café on Sophienstraße 27 in Berlin-Lichtenberg, we mainly drink coffees finished shortly after First Crack — light to medium roasted, with lively acidity and fruity aromas. 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.

Related Questions

• At what temperature is coffee roasted?
• What is the difference between light, medium, and dark roast?
• Why do coffee beans crack during roasting?

More depth on this topic in the article How to Make Perfect Espresso. Or stop by at Sophienstraße 27 — Mon–Fri 8am–5pm, Sat 10am–5pm.