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  • Good shots one day, gusher the next...

    Since upgrading to a Silvia a couple of months ago, there has been about 5 (250g) bags of coffee through the machine so far, and they have normally required about step 3 or 4 from the finest setting capable of my Breville Smart Grinder. The Nicaraguan beans I opened recently (roasted now 8 days ago) were no different for the first couple of days (from about day 3 or 4 from roast date), however literally overnight, something has changed (not sure what), and I've been experiencing nothing but fast pours ever since.

    I've tried up-dosing, grinding finer, up to as fine as possible from my grinder, and tamping harder, however it still pours a single in about 8 - 10 sec before I've hit the 30mL mark, and the pour has turned blonde. The naked PF tells me the distribution isn't too bad, and the pour is quite wide and central from the basket.

    I'm using the Rancilio 9 gm single basket, and until this latest bag, I was quite happy with my results. My normal dose is 9 - 9.5 gms, and I believe my scales are quite accurate. I've also tried down-dosing to 8.5 gm, as another thought I had was that maybe the screw in the group head was causing channeling through the centre when disrupting my dry puck. This is still my best hunch, but as of today, still cannot get those syrup-like pours I was achieving until recently.

    The post-shot pucks are fairly sludgy, which has been normal for single shots since owning this machine. I usually only make singles as I'm the only coffee drinker in my household. Yes they're more difficult to master, but I only need one shot at a time.

    Other than try different coffee, is there anything else I should investigate?

  • #2
    Did you leave the bag of beans open overnight?

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    • #3
      I don't think so, however it is now a few days since it all started, so I can't be positive. The beans are a little sweaty/oily actually.

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      • #4
        Are you confident that you aren't under-dosing the basket? Assuming that you have no headroom left to updose a little, why not try grinding a touch finer?

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        • #5
          Thanks Barry. I'm now at the finest grind setting and getting an 8-10 sec pour. I'm using the same dose, if not more than I was previously before this started. I'm wondering whether over-dosing may be causing channeling through the centre due to the group head screw causing a large indentation in the dry puck when I insert the PF.

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          • #6
            Hmmm, Might have to look into your tamping technique perhaps? I dunno, Would you be willing to video your process and put it up online so we can see what's going on and perhaps make suggestions from what we see? (yesyes, not tape, I have had my coffee this morning)

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            • #7
              Do the grinds look/feel similar to those from your earlier beans? if you pinch the ground coffee do you get any caking of the grinds? I'm just wondering whether the grinder is doing what it should. I'm not sure this matters with the Smart Grinder but sometimes with my K3 it helps to back the grinder off towards its coarsest setting then re-adjust it while grinding beans. Harmless to give it a go anyway.

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              • #8
                Does it start pouring good at the start then suddenly gush? If so, it may be a combination of grinding too fine and not distributing correctly. The water under pressure will find the path of least resistance which may be a weak spot in your puck. Common weak spots are the area on the basket near the handle.

                Above all, try using the double basket instead. An extra 9g is only going to cost you another 20c (or less) per shot and worth it if the result is better in the cup.

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                • #9
                  Thanks for all the input. Yes the grinds look and feel similar if not finer than what I've been normally using. A sick grinder is not out of the question though, given it choked on a rock recently. It's ground around 500 gm since, and there haven't been any issues until now. I might look into this if my next bag of beans gives me grief.

                  The pour is quite fast right from the start, and the stream is wider than normal.

                  Not quite ready to given in (too stubborn) to the double basket just yet, as it was going fine until a few days ago, but I'll certainly give it a go this afternoon. It's not so much the economics, but the principle of wasting a second shot.

                  A video is a consideration, though I don't have a very good one. I'm not sure how good it would be.

                  Edit: another thought is perhaps this coffee requires much finer grinding. My Smart Grinder is <12 months old, and I do have a shim kit which I have never needed to install. Just reading through the Smart Grinder thread, maybe it's time to give the shims a go.
                  Last edited by darrend; 14 July 2012, 12:23 PM. Reason: another thought

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                  • #10
                    Well now this has me puzzled.

                    I decided to explore both the grinder shim idea, and the double shot idea independently this weekend.

                    When I dis-assmebled the burrs, I discovered my Smart Grinder already had factory-fitted shims (1.0mm + 2 x 4.0mm). I played around to see whether I could fit any more, but was only able to add 1 x 0.2mm shim before the clearance became too small, and the top nut ran out of thread. Following this, when I tried brewing a single shot with varying quantities between 9 -10gm, I was not able to slow the shot any longer than 30mL/13 sec.

                    Today, I tried double shots. With the finest grind, and approx 19 gm of coffee, the flow was quite slow, and only just reached 30mL. Now acting like it may be back to normal, I again tried a couple of single shots, with 9.5gm coffee. It poured around 25mL in 30 sec, so surprisingly, with a little room to back off the grind.

                    This is all very strange, as it seems to be back to normal, and I cannot work out what changed (other than an additional 0.2mm shim in my grinder, which didn't work originally). I've been careful (at least I think) to maintain a constant grinding, dosing, tamping and temperature surfing technique during these "experiments".

                    I'll see how it goes over the next few days, but hopefully it was just a "glitch".

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                    • #11
                      Hi Darrend.

                      I had similar problems with my Silvia/SmartGrinder combo a while back just after I bought the grinder and was trying to set it up. I could NOT grind fine enough, and had 10-sec pours with a double basket. I farted around with shims, etc, but no luck. Eventually I tracked it down to having over-roasted my beans. They were quite oily on the outside. So, are you roasting your own? Can you change the beans to eliminate that variable?

                      Gonzo

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                      • #12
                        Weird.

                        Still, goes to show that in many ways, Good Coffee is an Art Form.

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                        • #13
                          The beans aren't roasted by me, but they were supposedly quite fresh when I received them. They do have a slight oiliness about them, and I'm not sure how much so is meant to be normal.

                          I'm about half way through this bag now, so will be trying a different region next time, and will see how they go.

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                          • #14
                            G'Day,

                            Have you fitted the shim kit to the Smart Grinder. We had a similar issue, Breville sent through the smart grinder shim kit.

                            The difference in grind is huge.

                            From what I understand is that Smart Grinders from early 2012 don't need the shim kit. Smart Grinders made last year need the shim kit.

                            John.

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                            • #15
                              My Smart Grinder is over 12 months old, but I discovered it already had a total of 1.8mm worth of shims factory fitted. I was able to add only 1 x 0.2mm shim before the tolerances became too tight/top nut ran out of thread.

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