When exposed to high relative humidity, such familiar foods as potato chips, dry breakfast cereals, and soda crackers exhibit an affinity for water. These and similar foodstuffs are manufactured using high temperature processes, so we expect that excess water has been driven out and the foods are dry. However, if these foodstuffs are allowed to remain exposed in a humid environment, even for a short time, they will absorb water from the surrounding air. Although the quality is not affected, these foods characteristically become soggy and rubbery and generally not very appetizing.

In processing such powdery foods as cocoa, gelatin, and dehydrated concentrates, the presence of moisture in the surrounding atmosphere can cause tiny particles of the powder to stick or cluster together, thus inhibiting their free flow in manufacturing or packaging processes.

Processing machinery can also be affected by moisture in the air, which can interfere with operation and obstruct the free and easy movement of the foodstuff.

Obviously, when moisture can have such a profound effect on food and/or machinery, the solution lies in conditioning the air surrounding the processing and manufacturing area.