A 3D Computational Fluid Dynamics (CFD) approach is used to investigate the effect of parameters such as bottle geometry, surface tension, or inclination on bottle emptying processes. The method can e.g. be used to assess changes of bottle emptying times induced by new bottle shapes, and it is shown to be much more accurate than existing empirical models. While expensive commercial CFD software has substantially restricted and hindered the use of this method in the past, our approach is based on freely available open source CFD software and hence accessible to everyone. (C) 2011 Elsevier Ltd. All rights reserved.