The rehydratability of a powder in water is an essential property of milk powders for the consumer. The stages of the reconstitution of powders can generally be categorized into wetting, sinking, dispersing and complete dissolution. There are four parameters pertaining to reconstitution: wetting, the penetration of the liquid into the powder, sinking of the powder particles into the liquid, dispersion of the powder particles, and dissolving of the particles in the case of soluble particles. The definition of wettability of a powder is the time required to achieve complete wetting of a specified amount of powder when it is poured into water at a specified temperature. Sometimes the term sinking is included in this feature, which means the capacity of the powder to be immersed in water after being wet. The wettability of commercial milk powders usually varies between 24 seconds for skim milk powder and 120 seconds for whole milk powder. The dispersion of commercial milk powder also