Slide 6 to zero: longer pre-infusion
On a LONDINIUM-R with digital pre-infusion module and wireless dongle & app you have the option to pre-infuse at a pressure of your choice (for instance 6 bar) and then immediately slide to 0 bar, in effect stopping the pump. This makes the pre-infusion last longer if you wish (for instance when playing with very light roasts). Then raise the lever as soon as the first droplet falls into the cup. Youtube version: https://www.youtube.com/watch?v=D6C4oloMOtM