Nuclear resonant inelastic X-ray scattering is a technique that enables us to resolve a vibrational density of states for specific elements in different materials. In the process of optimizing materials – as in the case of Collaborative Research Centre 270 HoMMage with regard to magnetocaloric materials for application in refrigeration – it is necessary to combine the work of materials scientists (who are experts in the preparation of the material), experimental physicists (who perform experiments like nuclear resonant inelastic X-ray scattering) and theoretical physicists (who provide density functional theory calculations, for example). Only through the interaction of these three parties is it possible to improve the materials  in an appropriate way. In doing so, nuclear resonant inelastic X-ray scattering resolves changes in an element-specific manner, looking at the vibrational properties over the course of a (first-order) phase transition. This approach is comparable to that of a chef looking at the changes of the waves in a béchamel sauce that is undergoing the transition from the liquid to the more solid phase while heating. And like a cook who knows the best properties for a béchamel sauce, one can determine the phase and corresponding properties of the material by means of nuclear resonant inelastic X-ray scattering. In combination with density functional theory and with the help of our colleagues from materials science, we are then able to optimize the magnetocaloric materials for the respective applications.