is a mixing process, commonly used in lube blending plants, that employs compressed air as the mixer. Air is injected into the bottom of the tank through multiple ports, and its upward movement through the liquid provides the mixing. If dry air is used, the process can remove entrained water from the lubricant. Nitrogen or an inert gas is sometimes used in place of air in this process. Sparging is not done with lubricants that contain volatile components (such as solvents) or that are susceptible to color change when heated and air blown.