sethde wrote: I'm not surprised you're getting more drips during preinfusion than you're used to, since the screens helps more evenly distribute water and increases saturation speed of the puck.

The piston in lever machines presses a column of water through the shower screen onto the puck. I'm not sure that part of the distribution (as opposed to what happens inside the puck) could be improved.

TomC wrote:In the electric world of a 3 way valve, one of these really reduce the amount of cleaning required due to fowling of the 3 way components. But in the simplified world of a piston/spring driven group lacking a 3 way valve, you're still benefiting not putting any ultra-fine coffee schmootz up there into the upper assembly which would likely increase corrosion on parts like the spring. I'd much rather keep that whole area clean and devoid of anything that exacerbates corrosion or wear on the seals o spring.

I'm not sure I understand. If you're saying that adding an extra layer of fines filtration can increase the risk of corrosion on vulnerable parts like the spring, I will argue that most Londinium and Pro800 owners already have a super fine filter simply by switching the generic shower screen to an IMS one.
The only way for the screen to be exposed to water is if the top seal fail. On the very rare occasions that this has happened, the small hole in the back of the group leaks water so you know right away that something is wrong.

I believe that less coffee grounds migrating upward is only good for the longivity of parts like the shower screen and piston seals.

LObin wrote:A commercial lever machine is quite low maintenance by design. However, there's always a bit of coffee grounds and oil that stick to the shower screen and inside the group. An open port flush (I do it with a portafilter wiggle) cleans most of it though.
...

Understood.

I'm thinking of keeping the Matrix shower screen for the same reason.

I use the bplus screen with my LR without any issues

Interesting.

Maybe the water distribution/force of the L1 (open loop thermosyphon) and the LR (close loop thermosyphon) when lowering the lever is not as similar as I thought...

I'll try to shoot a video later with the Flair 58 later.

K7 wrote:These filters probably reduce the water pressure as seen by the puck. Does anyone know by how much? Should be easy to measure if you have a Scace. I guess you would need a Scace-like device that can work with a screen in the basket.

Shouldn't be a problem to measure on Flair 58. Put the screen into empty basket, pour the water and 'pull the shot' normal speed, checking if the gauge moves. It will show total pressure difference on both screen and basket bottom

I doubt it will move at all

Alternatively, pull it with twice the speed and divide the measurement with 4. Or 3x speed and divide with 9 ...

Puck screens seem to be the latest hotness in espresso these days. I'm thinking that when I rebuild my Faema Faemina gaskets that I should try a puck screen since with the gommino arrangement on the piston the Faemina lets out a blast of water when you first pull the lever down and then stops until you pull it further down and I'm thinking a screen might help with puck integrity. I just need to figure out if my Faemina is a 51 mm or 54 mm since AFAIK I'm using the 54 mm basket and tamper on it from my Gaggia Factory.

Has anyone tried a puck screen on a Faema Faemina?

RyanP wrote:I use the bplus screen with my LR without any issues

What benefits do you get from that?
So far the biggest change I noticed when I use the bottom paper filter (it is measurable by extraction yield). I use matrix screen, mostly because it runs very clean and so far does not clog like IMS 35u.

Has anyone tried a puck screen on a Faema Faemina?

I have not, but I have had great results simply by tamping an aeropress filter on top of the puck. I used to cut them to size by tracing out my tamper, but I have started being too lazy for that and haven't had any issues. I notice it most during the fill-in portion of a bottomless portafilter. The fill-in with a paper filter protecting the top of the puck is much more even than without:



in this video, the no-paper filter is on the left and the paper filter is on the right. This also removes any need for me to flush the Faemina group after I finish pulling my shot to clear the shower screen and risk burning myself with the explosive flush, so its a win-win. I think the puck screen should work just as well. Oh, and I'm using a 51mm IMS basket and tamper on my 3rd gen Faemina

I've read through this entire thread as I'm having the same issue, but on an E61 machine with a vibe pump, using a 8.5mm grouphead gasket, some kind of fancy shower screen I think IMS, VST precision 18g ridgeless, and before the puck filter I could grind 18g into the VST, but now even if I drop my dose to 15.8-16g, 9/10, I'm getting water leaking out the side of the portafilter. Also, I'm noticing the first drips of espresso are collecting around the outermost perimeter of the basket, then move more center. Previously I was getting a more even extraction. Shots aren't terrible, but this really can't continue. Does anyone have any pointers?