Tea Time Gets Flavor Boost from Thin Film, Impure Water

In Physics of Fluids, researchers describe how they applied rheology to the seemingly quaint purpose of improving the quality of a cup of black tea. They describe the interfacial phenomenon in a cup left to cool after steeping, when a thin film at the air-water interface can form, and assess the mechanical properties of the film, the formation of which is affected by water hardness, acidity, sugar or milk, tea concentration, and brewing temperature.