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Gaggia Evolution & Grind

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  • Gaggia Evolution & Grind

    Ive inherited an old Gaggia Evolution espresso machine, with which Im having problems producing an acceptable espresso.  At this point I dont have a grinder, so Im getting the beans ground from Merlo (because its reasonably convenient to me).

    The basic issue is that it does a double shot in around 8 seconds, no crema.  This is using Merlos private blend ground for my machine (according to them).

    Ive resorted to using a finer and finer grind, however I am thinking there maybe there are other problems with the machine. I now ask Merlos to grind at 2.9, and they tell me (many times) that this is an excessively fine grind.  Ive never managed to choke the machine so far, so Im not sure whether what they are saying is true.  I know its not possible to compare grind settings without knowing what the grinder is (and even then it varies), but Ill try to ask them next time Im there what grinder they are using.

    My normal procedure is to:
    • Open steam wand valve, load empty PF and turn on
    • Turn on pump until water exits wand
    • Close wand and turn off pump
    • Let water reach normal brew temp (indicated by the boiler light)
    • Turn on steam element
    • Let water reach steam temp (indicated by the steam light)
    • Steam the milk
    • Turn off steam element
    • Turn on pump and open steam wand valve until water only (no steam) exits wand
    • Close wand
    • Wait until water only (no steam) passes through PF
    • Pull two shot glasses of hot water through PF
    • Turn off pump
    • Fill PF to top with coffee, level and sweep off excess (using double basket)
    • Tamp as hard as I can
    • Load PF into machine
    • Pull shot

    If I use a grind at 2.9, the above process gets me a double in 20 seconds with 1mm of crema on the top, however the pour doesnt look right - starts out like black water then turns creamy honey colour after about 10 seconds.  If I use anything coarser than 3.2, I get no crema at all.

    Ive tried pulling the shots before steaming milk (in case the water temp was too hot) and after steaming then dumping a shot (to get the temperature down), but no discerable difference that I can tell.

    The machine had a leaky steam valve and head valve (that spring with seal thing in the group head), both of which I have replaced.  Some improvement, but not much.

    Ive done a water debit test and the pump appears to be pushing through enough water.

    Obviously buying a grinder would be helpful, however Im concerned that I would need to spend a huge amount of money to get one that would be able to produce sufficiently fine grind for this machine.  I dont want to buy a grinder and then find out its not going to work either!

    So, does anyone have any other suggestions of things to try?  What do you think I might be doing wrong?

  • #2
    Re: Gaggia Evolution & Grind

    You will most likely get varied results using preground coffee.

    Even if you seal the ground coffee in an airtight container and open it only prior to using it, the coffee will age quickly and go stale, giving inconsistent results.

    Is there someone that you know with a grinder that you could trial with your machine?

    Your concern about "having" to spend a lot of $ on a grinder is right and wrong.

    You can get something like a sunbeam 450/480 for circa $120 - 180 I think, and that will "do the job" and get you better results than preground. If you can afford it, spend more on the grinder and aim for something like a Rocky / Compak / Ascaso etc.

    It has been said on here before that coffee once ground starts to deteriorate after 3 minutes, that figure may or may not be right, and you might be able to stretch the time out a bit by sealing it in an airtight container, but fresh ground beans used within the 3 minute rule will certainly get you better coffee.



    • #3
      Re: Gaggia Evolution & Grind

      Thanks for your reply Senator.

      I had expected as much - previously Ive used preground coffee from the roaster rather than the cafe and I got much better results.  Id imagine that the beans used by the cafe could be much older, and while beans do last for longer than ground, it all adds up!

      Now I just have to afford a grinder... might take a while with our first baby coming tho! ;D


      • #4
        Re: Gaggia Evolution & Grind

        I had an interesting result this morning.

        I prepared my latte as usual (as described earlier), however it looks like the group head gasket needs replacing.  As a result, I had some water leakage from around the group head while pulling the shot (clear water only).  As none of the leaking water fell into the glasses collecting the shot, I decided to drink it anyway.  The pull and the creama on the shot was better than usual, it also tasted very good as well.

        So what would this tend to indicate?  Im guessing that as a result of the group head leak, the water that actually passed through the beans stayed in contact with them longer and was perhaps at a lower pressure?


        • #5
          Re: Gaggia Evolution & Grind

          I borrowed a grinder for a few weeks from a friend.  As everyone here has pointed out, it does make a huge difference.  So much so that I dont think I would have believed it unless Id seen it myself.

          In my opinion, the pour is still too fast (so I guess I need to adjust  the grind a bit more), but Im getting that true "guinness" effect while it does pour and some crema.  The grind also doesnt look anywhere near as fine as Ive had to use with preground.

          My friend (who is no expert) tried using my machine and suggested that I also need to check the brew water temperature - he thought it was on the hot side compared to his machines (he has 3).

          So all in all, a useful result.  Now I just need to keep saving for that grinder!


          • #6
            Re: Gaggia Evolution & Grind

            The water temp on Gaggias can vary a lot so it really helps to do some temp surfing. I have found the following to produce a very consistent and suitable brew temp range (the cold water injection into the group guarantees that the temp will change during the shot).

            1. Grind/dose/tamp to setup PF
            2. Wait until the brew light is on (skip if already on!)
            3. Pump water through the group until the brew light turns off
            4. Lock in PF
            5. Pull shot as soon as the brew light comes back on.

            also then

            6. Switch to steam mode
            7. Empty out PF and lock back in (careful to avoid PF sneeze)
            8. Open steam wand until only steam comes out
            9. Steam milk when brew light comes on
            10. Switch back to brew mode when steaming finished
            11. Pull steam shot into the empty PF to help clean the showerscreen.