Defined as the perception of heaviness and viscosity in the mouth, body is affected by the amount of solids found in the coffee liquor, other emulsified constituents like oils, and certain chemical effects in the mouth. Cuppers often evaluate body by moving the tongue against the palate, applying pressure to the liquid against the surfaces of the mouth.
The perception of body in a free-flowing liquid is more the result of the uniformity of size of the particles than the concentrated amount of particles. During brewing, a number of solids become suspended in solution, oils are emulsified, and, in the case of espresso, gasses are extracted. Oils are mainly present in brewed products that do not employ paper filtration, such as French press and espresso methods. Dissolving of gases in liquid usually require pressurized extraction, as in espresso, and quickly dissipate or are held in crema by emulsifiers and oils. These oils and gases contribute to the mouth feel of crema in espresso, but there are differing opinions about their contribution to the overall mouth feel of the liquid.
Recent studies show there are more dimensions to the tactile sensation than body. These include the smoothness, syrupiness associated with simpler carbohydrates, and an after-feel sensation. These different aspects are especially important in the appreciation of espresso.
