The Matrix Shower Screen - Page 12

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cafeIKE
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#111: Post by cafeIKE »

I searched the thread and did not see it mentioned, but Cafelat e61 silicone gaskets have 3 notches on the inside which might not seal a screen with backpressure:


baldheadracing
Team HB

#112: Post by baldheadracing »

cafeIKE wrote:I searched the thread and did not see it mentioned, but Cafelat silicone gaskets have 3 notches on the inside which might not seal a screen with backpressure:
I used the Cafelat E-61 gasket, albeit the 8mm (red) version. No leaks, although I did notice that the portafilter did lock in at a slightly earlier position. I presume that this was due to slight production variations in the shape of the lip of the shower screen.

I need to play around with this screen some more ...
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

PIXIllate
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#113: Post by PIXIllate »

After 2 months of using the Matrix screen on and off (usually switching to my IMS nanocoated screen 1/2 way through a bag of coffee) I think I'm ready to offer some thoughts.

It should be stated that I did none of this blind, nor do I own a refractometer so all of this is based on my taste assessment.

I drink two straight shots each morning. They are pulled and allowed to cool while I clean up after the shot. The shots are then stirred with a spoon and allowed to settle for a minute before tasting. Most people would find my drinking temperature a bit on the cool side I suspect. I mention all of this just as a frame of reference.

Most of the coffees I've had over the past two months have come from https://zabcafe.com/collections/cafe but I've also had coffees from https://www.samjamescoffeebar.com/collections/beans and https://detourcoffee.com/collections/di ... ade-coffee in Toronto.

First of all it should be said that visually the flow from the Matrix is FAR more uneven that the flow from the IMS which produces very uniform, well spread out drops across the entire surface of the screen. My experience with the Matrix is that the flow looked nothing like the promo video where there is a large cone of water in the center. I found I got a series of "gushers" randomly spread out over the surface.

From an in-the-cup perspective I think that I'm ready to say that I prefer the Matrix shots for an increase in body and texture that repeatedly came up in my notes across all of the coffees. I also noted that the separate streams seemed to come together faster with the Matrix. Usually between 3-8g in the cup. With the IMS screen it's more like 4-10g in the cup. Please note I use a pretty fine grind on the Monolith most of the time and my shots usually run 17-18g in/27-32g out in 32-40 seconds with the OPV set to ~8.5 bar on my Profitec 600. I intentionally did not use the flow control at all while I was testing these screens and have generally found less and less use for it since receiving my Kafatek grinder.

In the end the problem for me is that the Matrix screen is TOO GOOD at preventing coffee from going back up into the group. Since using it I have had constant issues with a squeaky/sticky lever that is due to the e61 cam not having enough lubrication. I don't do chemical backflushes more than twice a year but I do water backflushes to start and end each session. I have not experienced this before other than maybe for a couple of shots after the chemical use. I tried to resolve this by taking the handle out and manually lubing up all of the parts. It did help but the stiffness came back after only a few days of use.

In the end I think that this is a deal breaker for me as I don't feel like taking the handle off twice a week to manually lube things up. So I liked what it did for the coffee but my e61 didn't like being starved of the coffee oils.

Hope this helps someone.
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coffeeOnTheBrain

#114: Post by coffeeOnTheBrain »

Did anyone ever note a minimal increase in pressure at the group when doing a flush? I have a Flow Control Valve installed and a pressure sensor at the e61 group and there is no increase in pressure on my machine. Somehow I would have expected something like 1.5 bar from the description how the matrix shower screen works.

Coffeebeanzzz

#115: Post by Coffeebeanzzz »

I'm glad you mentioned that about it being "too good" at stopping coffee stuffs from going up that it prevents the natural lubrication. Which makes perfect sense because for the first time since owning my machine the leaver on the e61 is now creaky and sticky. I couldn't figure it out but then I realized it started shortly after switching to the matrix screen. My question is: how do I fix this? I mean is there another option other than relubing the cam shaft thing all the time? Anyone else experiencing this and found a solution? I'd just assume switch back to the ims screen but I think I liked the matrix screens performance better and I liked that it wouldn't get as much buildup behind the screen

coffeeOnTheBrain

#116: Post by coffeeOnTheBrain » replying to Coffeebeanzzz »

Instead of backflushing just take the matrix out every once in a while and soak it in coffee machine cleaner for an hour or so.
Seems to work fine for me.

When I experienced my lever not moving as smooth I just used the old shower screen so long that it was smooth again :D

Coffeebeanzzz

#117: Post by Coffeebeanzzz »

Any tips on quicker better ways of removing the shower screen? I feel like I don't have the right tool for the job and am constantly worried I'm going to damage the screen in the process

baldheadracing
Team HB

#118: Post by baldheadracing » replying to Coffeebeanzzz »

-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

Tony163

#119: Post by Tony163 »

Really dumb question - how is that some shower screens appear to be held in by a center screw and others don't have a whole in the center for a screw and is read are held in with a gasket. If they are all E61s, should they all be the same?

baldheadracing
Team HB

#120: Post by baldheadracing » replying to Tony163 »

E-61's don't use a screw; they are held in by the group gasket. The screen and the gasket are removed together.

Some groups do the same, e.g., Pavoni domestic lever, Elektra domestic lever. The screen and the gasket are removed together.

Some groups don't use a screw, but are held in place by friction, e.g., most vintage lever groups. (Gasket does not need to be removed to drop the screen.)

Some other groups, e.g., La Marzocco, Rancilio, Elektra/BZ, etc., use a screw to hold the shower screen in place. (Gasket does not need to be removed to drop the screen.)

As the shower screen is removed and cleaned at least daily in commercial use due to the action of the three-way valve, the easier to remove screw design option is more popular in groups developed for commercial usage.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada