What factor is essential during the roasting process for each type of coffee?

Time and temperature are crucial factors during the roasting process because they directly influence the development of flavor, aroma, and the overall quality of the coffee. Each variety of coffee bean has its unique requirements for roasting, and the right combination of time and temperature helps to unlock the desired characteristics. Under-roasting can result in sour or grassy flavors, while over-roasting can lead to burnt or bitter notes. By carefully controlling these two variables, roasters can achieve a specific roast profile tailored to the type of coffee they are working with, ultimately impacting the cup's complexity and clarity.

While skill and knowledge are important for executing the roasting process effectively, they are secondary to the physical parameters of time and temperature that need to be managed accurately. The quality of beans and the type of processing are also significant but primarily affect the raw material before it reaches the roaster. Time and temperature are the critical factors that set the stage for creating the final flavor profile of each roast.