DavecUK I’ve seen your videos on the ACS levers, and recall you mentioning shot texture on that group being great. I think this is one thing some of us eventually work this out with a lot experimentation, finding a direct correlation with fill rates, pressure ramping, pressure applied over the course of the shot, group diameter, and puck depth, especially if we’re partial to espresso that has good body and texture. For what it’s worth, if I apply pressure even slightly more slowly, it can necessitate a 50+ microns tighter grind. That has quite a marked impact on shot flavor that can’t be dialed out with other parameters.
As Ive said a few times, my needs are atypical, so, I’m only providing my reasoning. What it means to someone else, is up to them.