Coffee Roast Levels
Roast levels are a function of time and internal bean temperature. As the bean temperature increases, it undergoes a chemical change accompanied by two releases of energy known as the first crack and second crack. Stopping the roasting process around these two events results in a range of commonly known roast levels. Apart from the underlying bean itself, roast levels can influence flavors in the cup. Generally, the darker the roast, the more the roast level influences flavor. For example most of Longbottom’s regional coffees are a Full City or Medium roast. At this roast level, the flavor characteristics of origin and processing can be identified and savored in the cup with minimal influence from the roasting process.
Cinnamon or Light Roast
This is the lightest roast and as the name implies, the beans are a deep cinnamon in color. The earthiness of the bean is forefront with wet grass, toasted grain and very bright character. The roast is stopped at the beginning of the first crack at an internal bean temperature is 383 degrees Fahrenheit.
Full City or Medium Roast
When the bean reaches an internal temperature of 427 degrees Fahrenheit, it begins the second crack. For a Full City roast, the roast is stopped right at the verge of the second crack at 428 degrees Fahrenheit. Typically, this roast is the best balance of time and heat to enjoy a coffee’s distinct origin with the roasting process unlocking as much of the organic compounds that define a coffee’s potential.
Vienna or Dark Roast
This roast is also known as a Light French Roast. The roasting process is stopped while the 2nd crack is underway and at this point the roast level begins to influence flavor. Distinct bitter sweet tones are present and acidity is neutralized. Internal bean temperature is 446 degrees Fahrenheit.
Here the roast level overtakes the bean’s natural flavor. Beans are dark brown, and oil covers the beans. As the beans are roasted to higher temperatures, caffeine content drops. Roasting is stopped at the end of the second crack at an internal temperature of 464 degrees Fahrenheit.
Approaching combustion, the beans are a very dark brown with burnt overtones coming to the fore. Oil covers the beans, acidity has been virtually roasted out. Internal bean temperature is 473 degrees Fahrenheit.