Backflushing Correctly – How Often, Really?Daily without cleaning agent, at home about every 50 shots with cleaning agent, in commercial settings daily – the CCC formula for... How the E61 Brew Group Works: Thermosiphon, Pre-infusion & 3-Way Valve Explained SimplyThe E61 group head explained simply – with an interactive animation: thermosyphon, lever with three valves, automatic pre-infusion, and around 9 bar...