hornbyben Mark-drinks-coffee I never understand why a clean screen is such a bonus, don’t you just move the muck? A quick flush and brush down and it stays pretty clean, then drop it once a week for a soak to keep it spotless. Doesn’t the puck screen get filthy? I’ve certainly heard that they’re hard to clean.
The puck screen (at least the mesh type one that I am using - it’s a cheapo from AliExpress) stops most of the coffee from touching the shower screen and from being sucked into the group (later being cleaned by a chemical backflush). I always wipe the shower screen with some tissue paper after a shot: without a puck screen I can visually see coffee on the paper, and with it I can’t.
When I do a chemical backflush after using the machine without the puck screen, the water comes out brown and dirty. After a few weeks with the puck screen, the water from a chemical backflush come out looking almost completely clean.
I am not saying nothing dirty goes through the puck screen, but visually it is clear that it’s far less.
I have not tested this thoroughly, but my common sense tells me that having less coffee residue from previous shots going into the current one is a good thing. A few times I didn’t pay attention and forgot to use the puck screen - the shot itself wasn’t impacted in a way that I could notice it, but it does annoy me because now I know I got my shower screen and group dirty, so whenever that happens I immediately drop the shower screen to clean it and add a water backflush for good measure (wiping cleans the bottom side, but what about the top side and the group?). I may be just obsessing here, maybe it doesn’t matter, but this is my personal experience.
And yes, the puck screen gets dirty. Most times it sticks to the puck and I need to fish it out of the knock box, but then it’s in my hand and I can wash it in the sink. I clean it after every shot with warm soapy water (as I do to the basket and portafilter), and it comes out clean (as far as I can see). I will then drop it in Cafiza when I clean the machine, but visually I can’t see anything coming out of it.
The analogy for me is similar to drinking from a dirty cup: I don’t want to wash my cup once a month/week/two days/every other shot. I want to always drink from a clean cup, and always make a shot as clean as I can, so I find the puck screen helps me with that. Am I an idiot? That’s very possible.