The present invention relates to a method and article for manipulating an amount of organic material entrained in an aqueous phase of a solvent extraction process. The method includes estimating an interfacial shear stress between an aqueous phase and an organic phase of a solvent extraction apparatus, estimating an amount of organic material entrained in the aqueous phase based on the estimated interfacial shear stress, and manipulating one or more solvent extraction process parameters to manipulate the amount of organic material entrained in the aqueous phase. The method and apparatus can be used to improve performance of and reduce operating costs associated with the solvent extraction apparatus.