Ever wondered how an E61 brew head works? What makes it different from other brew heads? How it maintains temperature consistently or releases pressure at the brew head? Or maybe you just want to know what the heck an E61 even is! Well, your questions are about to be answered, darling, with help of our good friend Bill Crossland. Not only is Bill a talented and knowledgeable mechanical engineer in his own right, he's also been working on developing a wide array of espresso machines for both the commercial and home markets for the past twenty-odd years. So when it comes to breaking down how the mechanics of an espresso machine work, we were lucky enough that he provided us this lovely tutorial! Using an E61 from a Rocket Espresso machine that has been cross-sectioned to show its internals, Bill walks us through the different components and functionality of this brew head. Watch to learn everything you wanted to know about E61's -- and possibly more! -- in this mechanically-focused video.