What do you like most about chocolate? Its crunchy texture? The sound it makes when biting? Based on these questions, scientists and researchers from the University of Amsterdam, the University of Delft, and Unilever have come up with the recipe for the perfect chocolate: crunchy and spiral-shaped.

The study, which has been published in the journal Soft Matter, shows that the mouthfeel of an edible substance can be designed. That is, it is possible to create metamaterials that are not found in nature, but are carefully constructed in the laboratory. The construction material they have chosen in this case is not wood, concrete, or glass, but chocolate.

The first step was to temper a mass with 72% cocoa and print it in the form of different spirals with the help of a 3D printer. The team then put the chocolate through a series of tests to see how it would break in the mouth if someone ate it, and concluded that pieces with more complex spirals broke into more pieces. They then tested the chocolate in different shapes on a group of people and found that the more convoluted the spiral, the crunchier it was and the more they liked it.

Corentin Coulais, the physicist at the University of Amsterdam who led the project, often works with shape-shifting metamaterials with applications for robotics, prosthetics, and electronics. This research opens the door to ways of designing food that is enjoyable to eat and, in general, to designing materials that optimize the interaction between humans and matter.