Foam stability reflects the water holding capacity of the foam and one way to determine the rate at which the liquid drains from it .
The liquid in foams is distributed between thin films and plateau borders.
Because of the radius of curvature of a plateau border, the pressure inside is less than that in thin films by capillary pressure.
This difference, known as plateau border suction, leads to drainage of liquid from thin films to the neighboring plateau border.
Finally, all liquid in the plateau border of foams are subject to drain of the liquid from between the bubbles caused by the action of gravity