Dark vs. Light Roast Coffee
There are just two species of coffee beans that are used to make coffee, and a huge variety of different types of coffees made from those beans, but all coffee comes from just those two types of coffee trees. The beans that are used to make coffee are actually the seeds inside coffee berries. When the beans are removed from the berries they are green and not viable for making coffee. Roasting is required to bring out the flavor and prepare the coffee for brewing.
When coffee beans are roasted, it changes the chemical properties of raw green coffee beans into roasted coffee. The roasting also gives coffee its particular taste, and the type of roasting can significantly change the final taste of the coffee. As coffee beans are roasted they change from green, then to yellow, tan and finally darker and darker brown. As the bean is roasted, coffee oil begins to appear on the surface of the bean giving coffee the aroma that coffee drinkers know so well.
Roasting is very important to the coffee’s final flavor. Premium Arabica beans such as Jamaican Blue Mountain and Kona are usually lightly roasted to preserve as much of the original flavor of the coffee as possible. More “generic” coffee beans, including most Robusta beans are roasted longer, influencing the coffee’s flavor more from the roasting process than the actual beans.
The terms “Light Roast” and “Dark Roast” refer to how long the coffee has been roasted. Light roast coffees contain more subtle flavors and tend to be more acidic. Roasting breaks down caffeine, so contrary to what many people believe, dark roasts have less caffeine than light roasts. Each type of roast has its own name amongst coffee connoisseurs. City roast is the lightest roast, American roast is medium and the darkest roasts are called Dark roast. There are many other names and variations of the different roasts, but they are all on the same spectrum of coffee roasting from light to dark.
--- Felix Sheffield