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  • Rocket Giotto Shower Screen

    Hey All,

    Just a quick question, struggling a bit to get some consistency on some of my shots on my giotto, some are amazing, some are so so...

    I found I have to use a pretty big dose to get some consistency (18-18.5g in a 15g VST) and the puck is just a sloppy mess when I dose less.

    Anyway, I had a look at the water flowing from the shower screen, and it seems a bit strange to me, certainly different to videos I see posted online, albeit not of the exact same model.

    So, am I over thinking, or do I have a potential source of my inconsistency problem?





    Scotty

  • #2
    Your Rocket Giotto is running a bit hot, that boiler is practically boiling out of the group and you might want to consider adjusting the pressure stat down a bit. That is probably why it looks a bit different. In the short term a really long flush before you make a shot might help.

    You could consider the 5c test to see if you are overdosing as it is likely the coffee is expanding up to the shower screen. I use a 20g VST on my Rocket Giotto and depending on the beans dose pretty close to 20 grams. I think you would be better grinding finer and dosing closer to 15g.

    Have a look at this article;
    https://www.baristahustle.com/blog/for-a-good-puck/

    In terms of your shower screen it doesn't look blocked but you can easily remove and soak in coffee cleaner or detergent over night and give it a good scrub with a group brush/toothbrush or a washing up brush.

    Comment


    • #3
      Originally posted by roosterben View Post
      Your Rocket Giotto is running a bit hot, that boiler is practically boiling out of the group and you might want to consider adjusting the pressure stat down a bit. That is probably why it looks a bit different. In the short term a really long flush before you make a shot might help.

      You could consider the 5c test to see if you are overdosing as it is likely the coffee is expanding up to the shower screen. I use a 20g VST on my Rocket Giotto and depending on the beans dose pretty close to 20 grams. I think you would be better grinding finer and dosing closer to 15g.

      Have a look at this article;
      https://www.baristahustle.com/blog/for-a-good-puck/

      In terms of your shower screen it doesn't look blocked but you can easily remove and soak in coffee cleaner or detergent over night and give it a good scrub with a group brush/toothbrush or a washing up brush.
      Brilliant, thanks for the response, it's my first 'real' espresso machine, so trying to get used to everything.

      I dialled the pressure stat down a little, and cleaned the grouphead/shower screen and it seems to be running a lot better now! Let's see how it goes in the cup



      Comment


      • roosterben
        roosterben commented
        Editing a comment
        Nice work on adjusting the PStat this will make a big difference to your coffee. Alot of older machines weren't bench tested and adjusted by retailers like they are today.

        Keep it up, the more variables you can keep constant the better. Keep an exact dose and if you can weigh your coffee in and out. You probably already have a routine but if you aim for 15 grams in and 25-30 grams in 30 seconds (38 if you count from the lever up and include pre-infusion) you are going to get some nice coffee out. To try and hit this window adjust you grind up/down and keep a consistent tamp weight.

    • #4
      Nice work with the videos, makes diagnosis 10x quicker and easier, and leaves someone else with the same problem a way to confirm it's the same.

      Comment


      • roosterben
        roosterben commented
        Editing a comment
        Yep agree with Ninja if a picture is worth a thousand words a video is worth even more. I can see the boiler pressure is sitting at about 1.1 bar which I run my Rocket at, this is a pretty good setting for decent steam power and little to no flushing unless the machine has been idle for few hours.

    • #5
      Originally posted by scotty595 View Post
      I dialled the pressure stat down a little, and cleaned the grouphead/shower screen and it seems to be running a lot better now!
      Early Giottos arrived in Australia without thermosyphon restrictors and ran hot as a result. They require a significant cooling flush.

      When you have it serviced, it would be beneficial to ask your service person to temperature test it and fit a suitable restrictor or restrictor set.

      Comment


      • #6
        Originally posted by roosterben View Post
        You could consider the 5c test to see if you are overdosing as it is likely the coffee is expanding up to the shower screen.
        By all means do the 5c test to get your dosing height correct. Dosed to the correct level (So the puck is not smashed into the shower screen when locking the portafilter into the grouphead and there-by fracturing it and causing channeling.) there will be no shower screen or shower screen screw impression on the puck after the portafilter has been locked into the grouphead while the puck is still dry. After the shot has been pulled there typically will be a screen/screw impression on the puck.

        But do not be fooled into swallowing the old myth that the puck expands up into the shower screen during brewing. It doesn't. As experiments done using a clear portafilter have conclusively proven there is no expansion of the puck until the extraction is completely finished. The expansion happens when the pressure, whether from a pump or lever, is stopped and the 3-way valve is opened.


        Java "Laying myths to rest one by one" phile
        Toys! I must have new toys!!!

        Comment


        • #7
          I changed the shower screen on my Giotto to IMS. It gives a much more even flow rather than the single stream from the stock screen. Something to think about.

          Comment


          • #8
            roosterben - yep, I generally try and keep as many variables as possible constant, I have a Puqpress so tamping pressure is pretty consistent, I'm still dialling in the doses and working with my Comandante to try get a good grind, but getting a lot more consistent now

            Comment


            • #9
              Originally posted by barri View Post
              I changed the shower screen on my Giotto to IMS. It gives a much more even flow rather than the single stream from the stock screen. Something to think about.
              Awesome, might give it a go, not too hard to change it over, took the old one out, cleaned it up, and put it back in within about 10 minutes

              Comment


              • #10
                Dose way less, and get fresh beans from local roaster. Forget the Vittoria supermarket crud.
                15g vst will take pretty close to that, not +20%.

                Comment


                • #11
                  Originally posted by Jackster View Post
                  Dose way less, and get fresh beans from local roaster. Forget the Vittoria supermarket crud.
                  15g vst will take pretty close to that, not +20%.
                  Yeah, I definitely buy fresh beans, living in Melbourne for a while made sure of that Haven't bought beans from a supermarket for about 5 years.

                  Dosing less now, and getting better shots, but limited by the Comandante's adjustment now, 1 click to the right gets me (in 18g VST) 18g in -> 45g out in about 40 seconds, group head pressure around 11-12 bar, 1 click to the left gets me 18g in -> 50g out in about 20 seconds, group head pressure 10 bar. *head explodes*

                  Time to get a proper grinder I think

                  Comment


                  • #12
                    You could try the click to the right and 15g in.

                    Or try the click to the left, 18g and reduce your pressure on the opv.
                    It's a bit of a balance sometimes..

                    Although the click to the right is pretty close to a lungo. Was that one tasty?
                    Last edited by Jackster; 2 weeks ago.

                    Comment


                    • #13
                      Originally posted by Jackster View Post
                      You could try the click to the right and 15g in.

                      Or try the click to the left, 18g and reduce your pressure on the opv.
                      It's a bit of a balance sometimes..

                      Although the click to the right is pretty close to a lungo. Was that one tasty?
                      Think I actually double corrected, and missed a click in between, also increased the pressure on the tamp slightly from 20 to 25 pounds and I struck gold...

                      18g in -> 45g Out, 25 seconds, looked like a nice even extraction through the naked PF. Tastes amazing Too bad it took my entire bag of beans to figure it out.

                      Click image for larger version

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                      • #14
                        Yep, 250g bags are too small!

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