A method for quantitative evaluation of emulsion stability using Critical Electric Field (CEF) determinations over a range of conditions, such as a range of temperatures, demulsifier compositions, or demulsifier concentrations. The method includes determining the CEF for a series of emulsions that differ substantially only in their internal phase volume ratio. A plot of CEF values as a function of the inverse of the internal phase volume ratio is characterized by a linear slope. Using the slope, a theoretical CEF value can be determined by extrapolating to where the inverse of the internal phase volume ratio is about one. The slope for a given emulsion series is associated with the relative energy barrier to flocculation and the theoretical critical electric field for a given emulsion series is associated with the relative energy barrier to coalescence. Comparative studies are performed using this method.