The espresso machine was patented in 1884 as a system for making coffee and presented at the General Exposition in Turin’s Parco del Valentino. Angelo Moriondo developed it for use in the café of the Hotel Ligure on Piazza Carlo Felice, opposite Porta Nuova train station. Since then, all sorts of research, alterations and improvements have been carried out in an effort to enhance its functions and – above all – to perfect the end product: our beloved espresso. But how does a professional espresso machine actually work? Essentially, a professional espresso machine forces pressurized water through a…