First and second crack of coffee beans, the magic of roasting revealed

Coffee Bean Roasting Process

Coffee bean roasting is to subject the raw beans to high temperature treatment to cause chemical changes inside them, thus producing the coffee aroma and taste we love. This process can be divided into two stages: first crack and second crack.

First explosion stage

First crack refers to the moment at the beginning of roasting when the coffee beans are exposed to high temperatures, the water begins to evaporate and creates pressure. This pressure causes tiny bubbles to form inside the beans, accompanied by a "crunching" sound. At the same time, the evaporation of water takes away some acidic substances, reducing the acidity of the coffee beans.

Second explosion stage

When the appropriate temperature is reached (usually between 200 and 220 degrees Celsius), secondary pressure builds up and causes a larger-scale reaction. At this point, more bubbles form under the heat source and are released at a faster rate. This release produces a larger amount of CO2 gas and water vapor, accompanied by a sound similar to an explosion. At the same time, the coffee beans begin to become more brittle and their appearance changes significantly.

The magic of baking

The chemical reactions and physical changes that occur during the roasting process give coffee its unique aroma and taste. First, during the first crack, the evaporation of water causes the acidity to decrease, making the coffee taste more balanced and softer. Second, during the second crack, the CO2 gas released adds a rich and full-bodied aroma to the coffee and forms the signature characteristic we often call "freshness".

In addition, some other important changes will occur during the baking process. For example, the increase in temperature will cause the decomposition of substances such as proteins and carbohydrates to produce aromatic substances; it will also cause the production of pigments, the reduction of bitter components, and other changes that affect the taste and flavor characteristics.

Different degrees of roasting bring different flavors

Coffee beans can present different flavor characteristics according to different degrees of roasting time and temperature control. Light roasting (Light RoaST) usually retains more of the characteristics of the original coffee beans, with higher acidity and a fresh taste. Medium roasting (Medium RoaST) balances the acidity and sweetness to a certain extent, and the aroma is more intense. Dark roasting (Dark RoaST) emphasizes the bitterness and cocoa flavor, while also reducing the caffeine content.

In short, the roasting process of coffee beans is a technical job that combines art and science. Only by mastering the key factors such as appropriate temperature, time and heat, and finely controlling them, can a satisfactory taste and aroma be produced. For coffee lovers, understanding and appreciating this process will undoubtedly allow us to better enjoy every cup of delicious and fragrant coffee.