Just curious if anyone else shares the same experience with me: when I single doze on my grinder, for the same flow rate through the espresso machine, I require a finer grind. When I fill my hopper up, I require a coarser grind for the same flow rate. The flavor separation is better for the finer grind through single dosing.
On a separate matter, it would be great if someone with pre-infusion ability on their machine (water plumb line pressure/variable speed pump with pressure control/fixed speed pump with pressure control valve going back to pump suction) can describe the impact of pre infusion on flavors of the espresso compared to without pre infusion (of course tastes are subjective but it would be great to hear some experiences)