SURFACE VISCOSITY AND GUSHING

Abstract

Surface viscosity correlates qualitatively with gushing induced by a standard gushing test. Substances which provoke gushing cause a large increase in surface viscosity when they are added to beer. Conversely, the very high surface viscosities induced by gushing agents fall to normal or intermediate values when anti‐gushing agents are added. High surface viscosity does not ‘cause’ gushing, but appears to be a frequent concomitant of the existence of stable nuclei. These observations support a hypothetical mechanism which suggests that anti‐gushing agents should be extremely surface‐active but incapable of forming a solid‐condensed surface film. 1972 The Institute of Brewing & Distilling