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Going insane with channeling, pls help!

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  • #16
    Have you popped the shower screen off to check if its clean, flip a tea spoon upside down a use it as a lever to pop off the shower screen from inside the group head.

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    • #17
      I agree if you've rotated the basket, changed your dose and tamp, etc, and it's still channeling in the same spot at the top of the basket, it's sounding more like it could possibly be a machine issue.

      Have you locked the handle in place and then removed it immediately to check that the puck isn't being disturbed before you make the shot?

      If the coffee isn't being impacted, per above, check the shower screen and dispersion screen. There might possibly be fouling, scale, dirt, etc causing water to jet out harder in that area of the basket?

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      • #18
        21 gms of "coarser" coffee sounds like it could be an overdose to me and the marks on your puck indicate this. As the water hits, the grounds swell and press against the shower screen causing the puck to crack.
        To check, after tamping, put a 5 cent coin on top of the puck and lock in. Remove and see if the coin is indented into the grounds. If it is, then an overdose is likely.
        As you are using a convex tamper, try this around the edge of the puck as well.

        Remember that changing the grind will change the *height* of the dose.

        Greg

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        • #19
          I have to say, the extra "oil in the shot" is something I usually get from overdosing (or rather, choking the machine). They usually end up in the sink.

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          • #20
            G'day "lucifuge"...

            I'd give the guys/gals at Cosmorex a ring and set up a training session with your kit and the coffee you are currently using. Just sounds like a technique issue to be honest, and with a bit of hands on training can probably be sorted out very quickly for you...

            Mal.

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            • #21
              Originally posted by lucifuge View Post
              OK, an update on subsequent attempts.

              1. .... Interestingly I did get some oils on the periphery of the crema that I don't normally get. But in short it was undrinkable due to channeling.

              2 ... Also need to dabble with a harder tamp as pnormal kindly supplied. (earlier quote): using a convex 58mm tamper
              Two thoughts here.

              1) The only time I have managed to get oils like that in the shot, the grinder needed either a major clean, a complete recalibration (including shimming in the case of several friend's EM480's) or new burrs.

              2) If you do a level, careful, initial / pre tamp of the first 2 to 3 mm of coffee using a flat tamper w about 3 Kg pressure, it will "almost universally" minimise channeling. FWIW, some of the research on curved tampers indicated it was an attempt to correct problems in the dynamic flow of grounds within poor baskets. I concur. One other observation, the photo you provided shows a "ring" of grounds around the top. That often affects channelling.

              Having said that, I am not at all familiar w your machine. What happened when you rotated the basket 90 degrees?

              TampIt

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              • #22
                Rotating the basket 180deg didn't change the position of the channeling; its still around 12'oclock.


                I did another attempt today; 20g + nutating + harder tamp pressure +finer grind. Had a minimal channeling spot, but still had ring indicating contact with the screen. But this coffee was best yet. Will try for 19g tomorrow!

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                • #23
                  I couldn't help but think a "nutating" tamp would create a worse distribution of grinds around the edge, this leading to a higher probability of side channelling. I'd go finer grind and lighter tamp.

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                  • #24
                    Try this,
                    Ignore supposed channelling issues as no-one can see inside the puck when making a coffee .

                    Holes, divots,cracks etc are meaningless if basic technique is wrong.
                    Ignore weights.

                    Grind your coffee into the portafilter so that it is slightly overfull.
                    Using the side of your finger as a scraper move the coffee around so that all holes are filled ( and the excess falls off )
                    and you are left with a smooth surface level with the top of the basket.

                    Do not push down.
                    Do not tamp !!!

                    Put the tamper on top and the weight of the tamper will compress the coffee slightly, then give it a twist. Do not push down.
                    Make a coffee.
                    If you haven't changed the grind, the shot will pull really fast. Discard the shot.

                    Adjust the grinder finer and pull / discard shots until you can pull 30ml using the above method in 25 - 30 seconds.

                    When you pull that shot do not release the portafilter until you have tasted the coffee.

                    If the coffee tastes fine ( and if you have followed the above it will ) the problem is solved.

                    It really doesn't matter what the puck looks like after the shot if the coffee tastes good.

                    John

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                    • #25
                      Something nobody seems to have mentioned - in your pic in the OP there is a ring around the edge where the grinds have been compressed. Look up into the group head and see what is causing that. It shouldn't be there. If you have something sitting in that groove it will affect the flow. Ideally the puck should not impact the shower screen enough to cause any indentation. The 5c test should leave an indent that is less than the thickness of the coin.

                      Try removing the shower screen (and the 2nd screen if you have one) and clean them, then hold them up to the light. Look for blockages. When i got my machine I washed those parts, but still had blockages in them until I took a brush to them and scrubbed the holes clean.

                      Check the filter the same way. My SB filters would regularly clog and took some scrubbing to clean all the holes - my VST one clean up far more easily.

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                      • #26
                        Originally posted by lucifuge View Post
                        Rotating the basket 180deg didn't change the position of the channeling; its still around 12'oclock.
                        The ring-shaped mild indentation indicates slight overdose, but that deep indentation that still appears at 12 o'clock points to an issue with your shower screen. Stop playing with grind/dose for the time being and check your shower screen. Is there something stuck under the screen at 12 o'clock? If there isn't, remove the shower screen and check for clogging. If the screen is clogged except for the 12 o'clock spot, water could be exiting the group head faster at that spot causing channelling. If it's something that can be cleaned, clean it.
                        Once that's sorted, start playing with grind/dose to finally eliminate the ring-shaped indent. BTW, you never mentioned what basket you're using (double or triple?). Is your basket actually rated to hold 20+ grams of coffee grounds?

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                        • #27
                          OK, I got shower screen off and am cleaning it in the cleaning stuff. I noticed no issues on the screen or on grouphead, both were quite clean and un-impacted.
                          Last edited by lucifuge; 19 November 2013, 03:37 PM.

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                          • #28
                            A video on removing and cleaning the e61 shower screen: Tech Tip: E61 Brew Head Maintenance - YouTube

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                            • #29
                              Originally posted by oble89 View Post
                              A video on removing and cleaning the e61 shower screen: Tech Tip: E61 Brew Head Maintenance - YouTube
                              Crikey, wouldn't let her within a country mile of my machine, what a clumsy removal of an E61 shower screen, all of that poking and jabbing with a screwdriver all it takes is the end of a teaspoon inserted where the PF bayonet lugs slot in, then lever on the bottom lip of the screen, first one side then the other, all up 5 seconds at the outside.

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                              • #30
                                But Yelta, those girls are the world's greatest experts on coffee machines!!
                                You know, like, they're on You Tube....................!!

                                ;-D :-D ;-D

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