 To be considered "dried", the final product must be solid, in the form of a continuous sheet (e.g., paper), long pieces (e.g., wood), particles (e.g., cereal grains or corn flakes) or powder (e.g., sand, salt, washing powder, milk powder).A source of heat and an agent to remove the vapor produced by the process are often involved.In bioproducts like food, grains, and pharmaceuticals like vaccines, the solvent to be removed is almost invariably water.