Hardness

“Hardness” is a physical expression for the amount of force that must be applied to a material in order to deform it in a particular way. The harder the material, the more pressure is required. In sensory terms, “hardness” is an expression for the force that is required to compress solid food between the molar teeth or softer food between the tongue and the palate. “Softness” is the opposite and describes food that is easy to compress.

The meanings of the words “crisp,” “crunchy,” and “crackly” are difficult to define, and they are often used arbitrarily with regard to many different types of food. This is an indication that our perception of the hardness of a particular material links and mixes together tactile, visual, and auditive sensory impressions.