The level of roast in a coffee is determined by time and temperature—the heat of the coffee roaster and how long the beans are left in. The art of coffee making requires using the precise level of roasting that best brings out the flavor of a particular bean.
The sugars in the bean are fully caramelized when a coffee is dark-roasted. This gives the roasted beans a bold, strong flavor, and body that can be addictive.
Dark roast coffees hold up well to additions like milk, sugar, and spirits.