Machine
Ponte Vecchio Lusso

Grinder
Eureka Atom 75

Regardless of how long I preinfuse, the first full pull always yields between 4 and 9 grams of espresso from 14g of ground coffee. The lever does not 'catch' until roughly 20% travel is remaining.
The second pull seems to yield around 15-18 grams of espresso, and the lever catches with about 50% travel remaining, much sooner than first pull.

This behavior is consistent, every time I make espresso with this machine. Observe this behavior in the video below. Any ideas?

Key details

• 14g fresh Saka coffee in
• Boiler pressure set at .9 PSI
• Brand new silicone piston seals, lightly greased with Dow Molykote 111 silicone grease, installed with pro jig
• False pressure always bled
• Warming pull always conducted after warmup and bleed to initiate thermosyhhon
• Recently descaled
• Water flows freely from grouphead when pulled with no portafilter
• I have never once pulled the lever when the machine is cold
• I have never once seen the lever slip/skip/jump upwards during a pull

I can think of a couple of things to try. I think you're not getting true preinfusion. Air remains in the system, including the puck. So the first half of your pull is occupied by expelling the air.

• Try grinding a bit coarser and see if you can begin to get some drops of espresso out before you let the lever go.
  
  I see you're preinfusing for about 5 seconds. Try doubling that.
  
  Increase the boiler to about 1.2 bar (but not much higher) or the group may overheat. This will require a change3 in your brew temperature management technique.

Caveat: I don't have the same machine as you, but my Zacconi Riviera (Eagle) has the same group.

Thank you!

Trying all of your suggestions tomorrow morning, will report with results.

I would inspect your siphon tube and see it it is cracked or not screwed all the way.

Looks normal. They require fellini's.I see nothing out of the normal in your video.

I would say that is normal function and roughly what is to be expected. I don't know how long you have been using the PV, but there are various methods to use, that can result in differences in the cup. Based on my own experience, here is my general procedure:

Dose 16+ gram (depends on the roast). With my usual N. Italian espresso blend, Musetti I dose 17-18g in double basket.
Lever down, wait a few seconds for the group to cool the water, then control the rise until 1 drop falls in the cup
Second lever pull, wait, control the rise until the puck is fully saturated and a nice pour could begin (nice to have bottomless PF for this)
Third lever pull, wait, let the lever rise on it's own.
Now it is adaptive management - if this pull is rising at the right pace, let it pour all the way. If it is slow, stop it half way and take a fourth pull.

This routine results in 20-30+ g espresso in the cup, and can be varied for more espresso. The dose and grind are important, of course. I've found it easiest to dose full, then do small adjustments to the grind to get the performance above.

There is air in the cylinder that must compress before the lever can "catch" as you describe, although I think the hole at the back of the group is designed to allow much of this to escape. Then, depending on the grind, the lever will catch sooner or later.

I know from experience that if you wish to know the "zero" point you can grind very fine and stall the lever. With a fine enough grind it will simply stop, and you will need to wait a while to remove the PF.

A few notes about your Key details:

14g fresh Saka coffee in: fresh is a relative term with Italian blends. Mine have "best before" not roast date. My current batch has a best before April 2025, which is "fresh", ie 18 months before the BB date. I think most roasters go 18 or 24 months. It is worth monitoring this. Also, if you happen to get a bag that has a pinhole in it, it will become worthless after a month on the shelf. I always test them for airtightness before I buy, then keep them in the freezer.
Boiler pressure set at .9 PSI you could raise the pressure, this will definitely make the cylinder fill more quickly and the lever catch at a lower point. I guess this is because some water is pushed back into the boiler at lower pressure just when the pour begins. Brew temperature can be managed by allowing the boiler water to cool in the group before you start the pull. The longer you wait, the more heat the group will absorb

All these points look correct:
Brand new silicone piston seals, lightly greased with Dow Molykote 111 silicone grease, installed with pro jig
False pressure always bled
Warming pull always conducted after warmup and bleed to initiate thermosyhhon
Recently descaled
Water flows freely from grouphead when pulled with no portafilter
I have never once pulled the lever when the machine is cold
I have never once seen the lever slip/skip/jump upwards during a pull

Your grind is too fine.

I have some observations to share after some 'testing' today.

Changes I made, per forum feedback

• Increased boiler pressure to 1.2 bar
• Loosened grind by two numbers on the atom (this would result in a significant change on my other machine, a Silvia Pro DB)
• Timed preinfusion at 10 seconds

Results
Exactly the same. Same volume, a little faster pour, but I'm not getting drips during preinfusion at all. Only once I release the lever.

Something really odd
In order to see if I could 'force' preinfusion drips with longer timing, I waited 25 seconds with the lever fully down before releasing - this time, the lever did not catch at all, and no espresso was produced! I waited a few seconds, and then pulled the lever down fully again, and the lever caught right away as soon as I released. Any thoughts on THAT?


Also, good to check up on coffee freshness, this coffee was roasted within the past month, no issues with the vacuum seal either.

peacecup wrote:I would say that is normal function and roughly what is to be expected. I don't know how long you have been using the PV, but there are various methods to use, that can result in differences in the cup. Based on my own experience, here is my general procedure:

Dose 16+ gram (depends on the roast). With my usual N. Italian espresso blend, Musetti I dose 17-18g in double basket.
Lever down, wait a few seconds for the group to cool the water, then control the rise until 1 drop falls in the cup
Second lever pull, wait, control the rise until the puck is fully saturated and a nice pour could begin (nice to have bottomless PF for this)
Third lever pull, wait, let the lever rise on it's own.
Now it is adaptive management - if this pull is rising at the right pace, let it pour all the way. If it is slow, stop it half way and take a fourth pull.

This routine results in 20-30+ g espresso in the cup, and can be varied for more espresso. The dose and grind are important, of course. I've found it easiest to dose full, then do small adjustments to the grind to get the performance above.

There is air in the cylinder that must compress before the lever can "catch" as you describe, although I think the hole at the back of the group is designed to allow much of this to escape. Then, depending on the grind, the lever will catch sooner or later.

I know from experience that if you wish to know the "zero" point you can grind very fine and stall the lever. With a fine enough grind it will simply stop, and you will need to wait a while to remove the PF.

A few notes about your Key details:

14g fresh Saka coffee in: fresh is a relative term with Italian blends. Mine have "best before" not roast date. My current batch has a best before April 2025, which is "fresh", ie 18 months before the BB date. I think most roasters go 18 or 24 months. It is worth monitoring this. Also, if you happen to get a bag that has a pinhole in it, it will become worthless after a month on the shelf. I always test them for airtightness before I buy, then keep them in the freezer.
Boiler pressure set at .9 PSI you could raise the pressure, this will definitely make the cylinder fill more quickly and the lever catch at a lower point. I guess this is because some water is pushed back into the boiler at lower pressure just when the pour begins. Brew temperature can be managed by allowing the boiler water to cool in the group before you start the pull. The longer you wait, the more heat the group will absorb

All these points look correct:
Brand new silicone piston seals, lightly greased with Dow Molykote 111 silicone grease, installed with pro jig
False pressure always bled
Warming pull always conducted after warmup and bleed to initiate thermosyhhon
Recently descaled
Water flows freely from grouphead when pulled with no portafilter
I have never once pulled the lever when the machine is cold
I have never once seen the lever slip/skip/jump upwards during a pull

Grind coarser. Preinfusion will cause the grinds to swell. The Silvia is no less than, and possibly more than 9 bar. The Lusso might be 6 at the start.

Keep moving the grind until you get full flow out

Have you pulled the lever without the portafilter? Are you getting a constant flow of water?

The only other thing I can think of is a thermosyphon stall. That usually gets cleaned with a flush.

Here a shot with the single basket.Looong pre infusion till the drops appear.With Fellini.Feel free to experiment.

Taste can be controlled with grind and temperature/ boiler pressure.
Your lever behaves perfectly fine in my eyes.