Close This Window Roast: Length and temperature of the roast. Light roasts provide more complex flavors, natural sweetness, less bitterness and higher levels of acidity. Medium roasts result in darker beans, more full-bodied and rounded acidity. Dark roasts are full-bodied, more dominant bittersweet flavors with the least acidity. Brightness: Level of acidity. Acidity, which is observed on the sides of the tongue, is a positive taste characteristic and is commonly confused with bitterness. When acidity is properly balanced with sweetness (for example, lemon juice is balanced with sugar to make lemonade), the result is an elevated taste sensation that is utterly delicious. Brightness can be influenced by roasting, but is an intrinsic quality in the bean. Generally, the darker the roast, the lower the amount of acidity. Body: The sensation of weight on the palate. A coffee that expresses a lot of weight on the palate is called "full-bodied." As a general rule, the higher the roast level, the fuller the body. Body can be influenced by roasting, but is also an intrinsic quality in the bean.