Probably is a problem with tamping & disc preparation. Occasionaly i had it with my old espresso machine.

I “upgraded” my stock Minima gasket and shower screen to a cafelat and IMS (not nanotech). Immediately had stuck pucks which I very rarely get with stock, even with the same bean. It is a relatively fine grind. I also noticed more water than usual on top of the spent puck.

Tried different beans and no issues so far. Will see how it goes - I have no issue returning to stock if need be. What @Rob1 said makes logical sense as to the cause.

Does anyone bother with a puck screen? I’d never considered one until I saw a Hoon video where he compares a Nomcore and Bravo tamper and it did pique my interest

    Cool. Just taken a look. Personally bot sure I’d want one for anything other than keeping the group clean and a nice puck. Mine tend to be a little soggy.

      dutchy101 Personally bot sure I’d want one for anything other than keeping the group clean and a nice puck. Mine tend to be a little soggy.

      Yeah I’m in the soggy puck brigade as well and let’s be honest, have a habit for buying accessories I can probably do without (£20-£40 is about the sweet spot for those kind of things!), so I’m sure I’ll end up with one at some point.

          I’ve just pulled the trigger on this. See what I mean? 🤣

          ￡13.27 60%OFF | 58mm Espresso Distributor Coffee Tamper Portafilter Stand Support Base Rack Coffee Filter Holder Corner Barista Tools

          https://a.aliexpress.com/_m07MEw4

          In my defence, the new distributor and tamper I’ve just bought did not have silicone mats so I need something to put them on. I also wanted a portafilter holder for sitting it in when doing wdt and preparing the puck. This fits the bill nicely and cost £15 as opposed to £50 on Amazon. The price of 2 silicone tamper mats was about the same

          @“Baldrick”#p6460th

          Baldrick thanks. I’m using an ECM Mechanika Slim. Vibration pump so pressure set at 10 bar

            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.

                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.

                  Thinking of getting myself a screen. I can see Shades of Coffee do them for about £6 (200 micron mesh) but wonder if the ridge around the circumference would be an issue.

                  https://www.shadesofcoffee.co.uk/stainless-steel-puck-screen-or-contact-screen-585mm

                  They also do another option woithout the ridge and in 50 micron mesh for £15

                  https://www.shadesofcoffee.co.uk/barista-tools/stainless-steel-mesh-puck-screen-or-contact-screen-585mm-575mm---50-micron-mesh

                    dutchy101 200 micron mesh

                    Notice that the first one you linked to isn’t a mesh type. It’s a sheet of metal with holes. The second one you linked to is a mesh (not saying that one is better than the other, I only have a mesh so can’t compare them).

                      Thanks I’ll look around and check the Ali Express too. Do you have any idea what impact the thickness / microns would have?

                        hornbyben Screens get really dirty on machines that vent back through the screen, the build up is behind where you can’t see it. Definitely affects taste after a while.

                        Contact me

                          dutchy101 Thanks I’ll look around and check the Ali Express too. Do you have any idea what impact the thickness / microns would have?

                          Mine is the 150 micron one, 2mm thick. I assume the 100 and 50 micron versions have even smaller holes? Can’t compare to what I don’t have, but on mine the mesh seems very fine. I can hardly see any light through it. Sometimes I have a little amount of water above it when I take out the portafilter after a shot, and the water looks clean, like it doesn’t mix with the coffee at all, so for me this is fine enough.

                            dutchy101 in theory they perform different functions. The thinner screens (first link) don’t seem to impact extraction and taste. I have the second screen (thicker) from shades and from limited testing it seems to improve the extraction and taste of lighter roasts at a straight 9 bars. More testing is definitely required although I wouldn’t use it with a medium or dark roast.

                            If you only want to keep the shower screen clean and prefer a firmer puck, I would go for the thinner and cheaper screen. Not sure of the impact if any of the solid border.

                            Your pucks should knock out relatively easily on the Minima though?

                            I forgot to mention, and this will be relevant to @PortafilterProcrastinator as well, the stock Minima basket is ridged and a lot of coffee can get stuck behind it when knocking out the puck - another reason to upgrade to a ridgeless precision basket.