Note - this is all changing for me - I just PIDed the boiler and running at 234 it seems that a 4 sec flush followed by a pull is best. I have also stopped pre-infusion because I feel on this machine the HX partially rebounding is messing with the pull.

Bottom line - probably don't take any of this advice, but experiment with different approaches.

Maybe this is the place to drop in and mention that for as long as I've been using my Livia 90, I have never flushed at all. When she reaches full pressure, I prep the puck and pull the shot. I had read that she was a dragon and that dragons needed to be flushed, but either my Livia is an oddity or that is not always the case. What I love about her is that she is so completely undemanding, and not at all what I had expected from an H/X.

I had a Maximatic (another dragon) at one time, and I can definitely tell you that there was a major difference; I could never get that one right. She and I did not get along, and I passed her along to someone with more patience for futzing.

So? Nothing except maybe try the easiest approach first.

Susan, can I ask what pressure your gauge peaks at?

Yikes, you might want to interpret the exact number, but it always stabilizes right at the 12:00 position on the dial

That's plenty close enough!!!! - so you are running about 1.25 and don't need an initial flush where I am (at this pull) running about 0.9 (PID 132) and find that a 1.5sec flush helps. Not what I expected! But that's espresso-ing!!! Thanks! This one was 18.4 -> 38g, 19sec from first drip, NO PI, thick and creamy. Cafevita Cafe del Sol frozen at +8days, roasted 7/7.

I note with amusement that I am back to trying Dan's suggested lower boiler pressure...