So why exactly is roasting a vital component in the preparation of espresso?
To answer this question, one must first understand exactly what the process entails. During the roasting process, the chemical components that determine aromatics, acidity, and balance are created and altered, in order to influence flavor and consistency.
This is accomplished in three stages; the first stage is the endothermic stage. In this stage, green beans are dried slowly until they become yellowish, emitting a slightly burnt aroma. The second stage, known as the first crack, occurs at around 400 degrees F. In this stage, the beans’ size doubles, while becoming light brown. Pyrolysis is the third stage, where the beans turn a medium brown, the chemical composition of the bean is altered, and carbon dioxide is released. These stages are followed by a short endothermic period, a second crack, and a second pyrolysis, where the beans turn a darker brown and gain an oily luster.
So what do these roasting phases mean as far as their effect on the taste of espresso? The degree of roasting enhances the aromatic and sweetness factors, while diminishing the bitterness and acidity. It’s important to find a balanced roast. Espresso requires a certain sweetness and aroma to achieve a satisfying experience. That’s why espresso drinkers add milk and flavoring to replace any lost sweetness that occurred during the roasting process.
Choosing the right roast is a very personal experience. What might taste great for one may be too sweet or bitter to others. The most important thing to consider is what tastes best for you!