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La Pavoni Bar T2

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  • La Pavoni Bar T2

    The Pav is has been running for a few weeks now. I still consider it on probation and am coming to grips with its ideosyncracies. I still have to replace the anti-vacuum valve with a new one. However, the way I use this machine makes this less of an inconvenience than actually shutting it down and replacing it (I have the replacement already). All in all, with the purchase cost and the restoration costs, this machine has cost me under $1000. As it has two E61 (variant) groups, its like having two Giottos side by side ;-)

    Now its not the prettiest of machines, even with the twin exposed manual E61 groups. Theres a number of plastic panels and the really crappy black plastic drip tray grills. Although at the heart of it is a very customisable HX machine.

    The things I like about it is the easily removed shower screens (via a screw) and the hollow E61 variant groups. By hollow youd have to refer to the La Pavoni parts diagram  on coffeeparts.com page 6. In this design the shower screen drops off followed by the shower head which in turn fits into another hollow fitting that then fits into the bottom of the group. This part actually holds in the group gasket and makes gasket changes quite easy.

    Another thing I like is the use of thermosyphon flow restrictors. These are small discs that fit into the back of the group where the thermosyphon lines connect. It is currently fitted with 3 mm restrictors. Smaller apertures will make the group cooler, while larger will make it hotter. Eventually Ill make a few up in the lathe so that I can have a set to customise the group properties.

    The main draw of the manual E61 is the mechanical pre-infusion. Its really cool to hear the pre-infusion happening when you flick the lever. The sound probably comes from the flow through the jet/gicleur as the pre-infusion chamber fills. The sound is like a "swish" that ascends in pitch over about 2-3 seconds. If I source some smaller jets (say 0.6 mm), this pre-infusion period will be lengthened further. Currently Im using 0.7 mm jets.

    Steaming wasnt such a huge difference compared to the BZ35. I was already running a 4 hole tip on that so the swap over has me making nice micro-foam and thicker cappuccino quality foam quite easily. I like it. One of the things thats hard to describe is the feel of the steam and water taps. These commercial valves actually close themselves. Its really cool they way they operate.

    Lastly, at the pressurestat setting Im currently using, (switching off at just under 1 bar), the cooling flushes are only about 100 -150 ml. Thats very easy to manage. I may increase the boiler pressure a bit to make it easier to hit higher temperatures. I really havent done any work on this machines thermal performance yet. I have to get the third portafilter converted to a naked, so that I can use my thermo-filter-like attachment.

    Anyway heres some pics of the beast,


    A different view showing the cheap plastic panel and a missing lower panel. The trusty La Cimbali Cadet grinder is sitting next to the machine.


    OK, so heres a part of my lair. This is the table that holds the Pav and an experimental machine that Im working on. Theres quite a lot of parts visible as well. Im going to clean up this room a bit and move some of the spares to my dingy workshop (area 52).
    Otherwise what will guests think...



  • #2
    Re: La Pavoni Bar T2

    Sparky, methinks you are underselling La Pav. She looks pretty pretty. I think the exposed chrome groups reflecting in the chrome backsplash panel look superb.

    I see you use the same timer as me -- I use it for timing roasts, extractions, water debits, elapsed time between pressurestat KLUNKS, element-on cycles and on it goes.

    But back to the Pav, it really merits a more majestic setting befitting its status.

    --Robusto

    Comment


    • #3
      Re: La Pavoni Bar T2

      Wow Sparky, that experimental machine looks mysterious - is that wired to... pick up vthe intrastellar vibrations from the godzone shot controller?

      Comment


      • #4
        Re: La Pavoni Bar T2

        The experimental machine uses a PID controlled Sunbeam EM6900 thermoblock, which is sitting on top of the machine in this picture, and a PID controlled Silvia boiler to preheat the water fed into the thermoblock. That way I can experiment with the thermoblock and see just how it copes with different pre-heat levels. So far it doesnt seem to need any pre-heating, but for better temperature control, I suspect preheating might improve things a bit. Im still tweaking with the group and thermocouple mounts, so the machine isnt running at present. It will be soon though.

        As a side bonus the twin PIDs will be accurate enough to stabilize the temperature to the point that the machine will be able to detect gravity waves as small thermal fluctuations. The machine will be wired to  the internet and will interface to the LIGO experiment to be used as an additional crosscheck on their data.  

        Cheers,

        Mark.

        Comment


        • #5
          Re: La Pavoni Bar T2

          Ive heard that theres a mod floating around out there to convert your portafilters into packetfilters for when closed cell foam isnt enough of a firewall. ;D


          Java "Whistling aimlessly while staring off into space." phile
          Toys! I must have new toys!!!

          Comment


          • #6
            Re: La Pavoni Bar T2

            wow, im not entirely sure wot price range your experimental machine will fit into, but it sure sounds extreme! What chassis is it encased in? did you make it yourself?

            Comment


            • #7
              Re: La Pavoni Bar T2

              ....And theres a rumour doing the rounds that it willl also interface to the synchrotron, though I believe the eggheads there have reservations about their resolution being good enough for the Twin-PID Experimental Coffee Module.

              --Robusto

              Comment


              • #8
                Re: La Pavoni Bar T2

                Originally posted by robusto link=1175222893/0#6 date=1175500604
                ....And theres a rumour doing the rounds that it willl also interface to the synchrotron, though I believe the eggheads there have reservations about their resolution being good enough for the Twin-PID Experimental Coffee Module.

                --Robusto
                Yes, .001C is just not good enough. :

                Comment


                • #9
                  Re: La Pavoni Bar T2

                  The frame is from an old Bezzera Minibar. Similar to the one Mal is currently restoring.

                  The goal is to have a stable and settable brew temperature to go searching for the red crema zone. Im no fan of calibrated flushing of HX machines. Sure they make a pretty good coffee, but once youve driven a temperature stable machine like a La Marzocco, youll never want to go back.

                  My two options for a stable machine are my Faema Family and the Sunbeam. The Faema is currently awaiting some further mods as well.

                  Cheers,

                  Mark.

                  Comment


                  • #10
                    Re: La Pavoni Bar T2


                    Update on the Pav.

                    Ive set the pressurestat to 1 bar. My pressurestat has a wide dead band of about 0.25 bar, so the average pressure is closer to 0.9 bar. This setting is pretty good. It requires only a modest flush of maybe 150 ml initially and only about 50-70 ml (if that) for successive shots. The shots are coming out pretty damn nice as well. Ive at least gotten back to where I was with the BZ. Ive also been brewing at higher temperature than Id been using before, with excellent results. The crema is coming out darker with very pronounced tiger striping. When I keep the mouse and rats tails at bay, the shots are pretty tasty. Im still searching for that really red crema that Id stumbled across earlier on. It may mean another tweak of the pressurestat to give me a bit more head room to play with. Nevertheless, I did a run of three shots today and by the third, Id gotten a nice darkish crema with redish tiger striping that tasted quite smooth with no grasssiness or sourness and none of that nasty bitterness. Those few red crema shots have been sweeter though, so Im not there yet.

                    Ive been playing with another feature of the E61 levetta group and that is extra pre-infusion. This works by starting the brew process by flipping the lever, then about 3-4 sec from the start, before the shot starts to flow, switching to the middle position of the lever for about 2 sec. This position closes the brew valve without opening the exhaust valve, so the pressure is given some additional time to soak the puck. Then I just flick the lever back to the brew position and it continues on its merry way. This is one of the interesting things with full manual control. Im not sure if it will be beneficial, but at least its another thing to muck around with.

                    The bottom line is that the Pav is performing at least as well as the BZ. Sure its overkill for a home machine, but this is the EXTREME machine category.

                    I also played around with my experimental machine again today. The mods I did were to remove a large chunk of metal from the group adaptor flange to minimise the heat loss, and move the temperature control point closer to the thermoblock/group junction. It did improve things a bit, but the brew temperature still increased during the shot. My feeling is that either I use two set points for the PID. One to keep the group at the appropriate temperatre and the other that is activated when the brew button is switched is the required brew temperature. Otherwise, the only solution will be to independently heat the group. This is probably the best option and will require resurrecting the Minibar boiler and group.

                    All good fun.

                    Cheers,

                    Mark.

                    Comment


                    • #11
                      Re: La Pavoni Bar T2

                      Originally posted by Sparky link=1175222893/0#9 date=1176120979
                      Update on the Pav.

                      (edited)
                      Ive been playing with another feature of the E61 levetta group and that is extra pre-infusion. This works by starting the brew process by flipping the lever, then about 3-4 sec from the start, before the shot starts to flow, switching to the middle position of the lever for about 2 sec. This position closes the brew valve without opening the exhaust valve, so the pressure is given some additional time to soak the puck. Then I just flick the lever back to the brew position and it continues on its merry way. This is one of the interesting things with full manual control. Im not sure if it will be beneficial, but at least its another thing to muck around with.
                      Its a more romantic notion, standing by the machine, pulling and pushing levers, exercising control, subjugating the brew to your will.

                      Mmmm... I think that beats extending the index finger and pushing a soft-touch button.

                      -Robusto

                      Comment


                      • #12
                        Re: La Pavoni Bar T2

                        Originally posted by robusto link=1175222893/0#10 date=1176190393
                        Originally posted by Sparky link=1175222893/0#9 date=1176120979
                        Update on the Pav.

                        (edited)
                        Ive been playing with another feature of the E61 levetta group and that is extra pre-infusion. This works by starting the brew process by flipping the lever, then about 3-4 sec from the start, before the shot starts to flow, switching to the middle position of the lever for about 2 sec. This position closes the brew valve without opening the exhaust valve, so the pressure is given some additional time to soak the puck. Then I just flick the lever back to the brew position and it continues on its merry way. This is one of the interesting things with full manual control. Im not sure if it will be beneficial, but at least its another thing to muck around with.
                        Its a more romantic notion, standing by the machine, pulling and pushing levers, exercising control, subjugating the brew to your will.  

                        Mmmm... I think that  beats extending the index finger and pushing a soft-touch button.

                        -Robusto
                        Just dont get distracted.
                        I did the other day when trying something similar.

                        I flipped the lever to the half way point and intended to leave it there for a few seconds before I moved it to full on.
                        My daughter rang and distracted me for about a minute.
                        By the time I got back to the machine it was already dripping and as I hadnt even put a cup in place I have no idea how long it had been going.
                        Assuming (I know I shouldnt have) it had only just started, I moved the lever right up and learned what the term "gusher" means.  ;D
                        Worst shot Ive ever pulled.

                        The strange thing was that the puck showed signs of channelling but I thought preinfusion allowed the puck to gently expand before being hit with the full extraction pressure.
                        I suppose it might just have been a bad tamp or was already over extracted.

                        Comment


                        • #13
                          Re: La Pavoni Bar T2

                          Over-extracted would be an understatement for that one.

                          -Robusto

                          Comment


                          • #14
                            Re: La Pavoni Bar T2


                            Yesterday I just noticed a great way for estimating the rebound (ie how fast the temperature in the heat exchanges recovers back to steam boiler temperature). After a reasonable flush (say 200-300 ml), you can see the cold water heating up before your eyes by looking at the brew pressure gauge. As the water heats, it expands and the pressure increases until the expansion valve opens to relieve it. Its interesting to watch and you could probably even get quantitative if youre serious enough.

                            Comment


                            • #15
                              Re: La Pavoni Bar T2


                              Now to dust off this old thread. While the Pav has been put into work horse mode, Im still tweaking and adjusting (according to taste). I raised the pstat to 1.1 bar a while back and thought things were well. However, after a more serious espresso tasting session with a mate, we came to the conclusion that the Pav was brewing too hot. So I started adjusting back down to a more reasonable level. I stopped at around 0.9 bar (element switch off pressure) and all seemed much better. At this pressure there is virtually no super hot water exiting the group. This is at odds with my old BZ35, which had a definite "water dance", requiring a well timed flush to hit the target temp. The Pav seems to defy that. Today I finally got around to doing some crude thermologging, using a calibrated TC over the lip of the basket. I had a few shots worth of stale coffee to clear out of the grinder, so it seemed an opportune time.

                              It seems the taste bubs dont lie. The brew temp is virtually flat after about 10 sec (before which there is a hump of about 1 oC). And the target temp... 94 oC. So within the range of acceptable brewing temps... just. This target temp seems to be invariant regardless of the amount I flush. I guess its those huge 300 ml HX tubes. As I said in another thread, this machine is designed to mix cold and hot water to get the proper brew temp. This means the machine hardly needs a flush, but it also means that its hard to change the brew temp except by altering the pstat... For commercial situations, this is fine. However, when the beans are different on a week to week basis, this is a pain... However, I have a solution in mind.

                              Ill post the 3 shot series up soon.

                              Cheers,

                              Mark.

                              Comment

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