Defoamer Chemical is a typically inert compound. A defoamer that is effective should be insoluble in the medium it is defoaming. A defoamer must have an Entry Coefficient larger than zero and a Spreading Coefficient bigger than zero in order to function. Because of the problems caused by foam, defoamers are required in numerous sectors. Stable foam makes it difficult for a fluid system to function properly, resulting in product loss and potentially hazardous circumstances in a facility.