A dark roast bean is roasted to the point that the oils within the bean have darkened. This produces a smooth, not bitter, cup of coffee. The oils are burned, but the process is stopped before the bean burns. This technique is a traditional method in making coffee since it’s one of the best methods for preserving the bean. In comparison to light roasts, dark roasts have more caffeine, more acid and more oils. A dark roast has a thicker body, like a syrupy, mouth-filling sensation. The light roasted coffee is brighter, more lively.