Predictive performance of a free-surface simulation technique is assessed using the volume-of-fluid (VoF) method, in the context of a challenging, yet simple and well-defined, unsteady-flow configuration mimicking the in-mouth kinematic processes occuring during the consumption of liquid foods. An experimental "mouth-analog" setup consisting of a cavity initially filled with a liquid and agitated by a rain moving periodically was modeled and simulated. Experimental and computational results are compared for a range of liquid viscosities (silicon oil and water) and over a range of processing conditions (low- and high-agitation frequency) that trigger important effects such as surface reconnection and breakup, wall coating, filament formation, and air inclusion. Even with the large mesh and time-step sizes used in the computations, the main relevant bulk kinematics of this complex transient free-surface flow can be represented with a Eider volume-tracking method such as the VoF method.