What Is a Defoamer

Defoamers, antifoaming agents, and air release agents are chemical processing aids used to reduce or eliminate foam in industrial processes. Although these terms are often used interchangeably, they operate through different mechanisms, making it useful to distinguish between them.

Defoamers are foam control agents added to a system to reduce or eliminate foam after it has formed.
Antifoaming agents are foam control agents added to a system or formulation to prevent foam from appearing in the first place.
Air release agents work by helping to remove entrained gases from a solution and bringing them to the surface.

These categories are not strictly exclusive. Many chemical formulations, for example, both prevent and destroy foam, allowing them to be classified as both antifoaming agents and defoamers. In addition, many defoamers also affect entrained air, while some air release agents contribute to the destabilization of surface foam.

For simplicity, the term “defoamer” is commonly adopted as an industry standard when referring to any processing aid designed to control foam.