The Determination of the Effective Shear Rate in the Brabender Viscograph and in other Systems of Complex Geometry

The effective shear rate in the Brabender Viscograph has been determined as 40 sec−1 when used for fluids having equivalent Newtonian viscosities in the range 1–30 poise. This shear rate is close to that used in the mouth and implies that rankings of viscosity derived from Brabender readings will agree with sensory consistency judgements. The instrument can, therefore, be reliably used for quality control and be quoted in purchasing specifications. The methodology described can often be used in other situations for assessing an effective shear rate where the geometry of the system precludes calculation e.g. spreadability determinations and extrusion from metal tubes.