The dribbling of tea down the side of a teapot while pouring—known as the teapot effect—is a minor annoyance for regular tea drinkers. But for physicists around the world, it has posed a knotty theoretical problem spanning decades of research, garnering an Ig Nobel Prize along the way. We thought researchers had finally closed the book on the mystery of the teapot effect in 2019, when Dutch physicists came up with a quantitative model to accurately predict the precise flow rate for how much (or how little) a teapot will dribble as it pours.

But apparently there was still more work to be done to fill a few holes in the theory, and physicists at the Vienna University of Technology (TU-Wien) and University College London took them on.