Desiccants are compounds or agents, such as Montmorillonite Clay or Silica Gel, used in facilitating low-humidity
environments by adsorbing moisture content from the air. Typically used in transport, storage, or maintenance
of materials and products, desiccants are used to keep everything from gym shoes to military munitions dry.
A desiccant is a hygroscopic substance that induces or sustains a state of dryness (desiccation) in its vicinity; it is the opposite of a humectant. Commonly encountered pre-packaged desiccants are solids that absorb water. Desiccants for specialized purposes may be in forms other than solid, and may work through other principles, such as chemical bonding of water molecules. They are commonly encountered in foods to retain crispness. Industrially, desiccants are widely used to control the level of water in gas streams.
One measure of desiccant efficiency is the ratio (or percentage) of water storable in the desiccant relative to the mass of desiccant.