Non-Newton flow behaviour of beer

Although beer is considered being a Newtonian fluid, it can be shown that m echanical stress in the laminar flow through porous media (packed beds of s uperfine glass spheres were used to simulate the porous structure of kiesel guhr) can evoke a distinct non-Newtonian flow behaviour: This phenomenon is coupled with partly irreversible changes of the colloidal structure of bee r and a strong increase of flow resistance. These micro structurisation pro cesses and the increase of flow resistance are both caused by the elongatio n of colloidal beer compounds through elongational forces in the flow withi n the pores. The results of this study lead to the conclusion that filterab ility of beer is dependent not only on shear viscosity but decisively on el ongational viscosity.