Foam control agents containing Degussa's SIPERNAT® performance silica and AEROSIL® fumed silica lines are a cost-effective means of preventing foam production problems. This bulletin provides detailed information on: the theoretical aspects of foam and defoaming; Degussa silica that can be used to produce defoamers; how those products are used; the functionality they deliver; and the application and technology tests conducted by the company in its laboratories.