Components of Coffee Taste
A coffee's flavor describes the overall and combined sensations/perceptions of the coffee's distinctive aromatic and taste characteristics, the fusion of body, acidity, aroma, bitterness, sweetness, and aftertaste. A well-balanced coffee is one in which no single flavor characteristic dominates and/or overpowers/overwhelms the others.
Body
The term body describes the physical properties – heaviness, or mouthfeel – of the coffee as it settles on your tongue; the feel of the coffee coating the tongue, and whether it is oily, grainy, watery, or possesses some other characteristic.
Acidity
Acidity is a desirable primary coffee flavor sensation that is perceived as a pleasing sharpness toward the front of the mouth, a numbing sensation on the tip of the tongue, or a dryness at the back of the palate and/or under the edges of the tongue; denotes the quality of a gourmet coffee.
Aroma
Aroma is the smell of freshly-brewed coffee.
A coffee's aroma, which may range from herbal to fruity, is created by the coffee's volatile components – vapors and gases – which are released from the brewed coffee and then inhaled through the nose where they come in contact with the olfactory membranes.
Bitterness
Bitterness is a primary flavor sensation, perhaps a twinge or aftertaste, primarily detected/perceived on the soft-palate toward the back of the mouth, and characterized by a solution of quinine and caffeine as well as other alkaloids.
Bitterness is one of the four basic tastes – sour (tartaric acid), sweet (sucrose), salty (sodium chloride), and bitter (quinine) – detected at the back of the mouth.
Bitterness is desirable in a coffee to some degree, particularly in a dark roast or espresso. In general, Robusta (Coffea canephora var. robusta) coffee beans are more bitter than Arabica Coffee beans.
Sweetness
Sweetness is a mild, smooth coffee flavor characteristic/taste sensation (a basic taste descriptor) without any harsh tastes (e.g., Rio flavor) or flavor defects/off-flavors. This sweet quality is often perceived as a palatable and/or fruity taste that is sensed primarily at the tip of the tongue.
The term sweet is used by cuppers (professional coffee tasters) to describe the intensity of the sugary qualities of the coffee when it is swooshed around in the mouth.
Aftertaste
A coffee's aftertaste, also called the finish, is a taste that remains in the mouth subsequent to swallowing a sip of brewed coffee. Aftertastes range from chocolaty to carbony, turpeny to spicy, possibly with hints of caramel, fruitiness, smokiness, roastiness, and other flavors.
A coffee's aftertaste is created by vapors and gases – volatile organic compounds – from the ground and brewed coffee beans. These vapors that create the aftertaste are released from the residue that remains in the mouth after swallowing the coffee.