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VBM Domobar Jr - ? burnt coffee

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  • #31
    Re: VBM Domobar Jr - ? burnt coffee

    Originally posted by 6F77797070651C0 link=1267828746/29#29 date=1268632075
    IMPORTANT:

    someone please check this, and correct me if im wrong...

    1. The Pressurestat screw is on the upper right of the machine, underneath the warming tray. (on my Junior, the pressurestat says "Mater" on it &DEC 08).

    2. The pressurestat controls the boiler pressure/temp, which should be 1.5 bar, as indicated by the gauge on the upper left of the machine.

    3. Turning the screw CLOCKWISE INCREASES the brew pressure/temp (because it makes the boiler click on at a lower pressure)

    (i just had a look using a torch, and saw that the pressurestat has a + and -sign with an arrow, indicating clockwise is "+")
    Correct you are skelly,

    The junior has a Mater p/stat and clockwise increases pressure.

    Your machine settings are bizarre and reek of no bench test to me. Set the boiler pressure to about 1.2 bar at max. System pressure should read about 10-10.5 bar- which will lead to circa 9 bar at the group...

    Did your machine vendor forget about a bench test and sell you a box only?  :-?

    Chris

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    • #32
      Re: VBM Domobar Jr - ? burnt coffee

      Cheers Chris!
      I was told it was set up and tested, but it certainly arrived too hot (and packaging was factory fresh).

      Ive now adjusted it down to 1.2 (max) and 10.3, and the two shots i pulled 10 mins ago were noticeably more consistent in colour & flow rate.

      oh well! its been a learning experience, and the coffee has actually been very good even with the settings being all wrong!

      Comment


      • #33
        Re: VBM Domobar Jr - ? burnt coffee

        Originally posted by 627A747D7D68110 link=1267828746/31#31 date=1268634440
        Cheers Chris!
        I was told it was set up and tested, but it certainly arrived too hot (and packaging was factory fresh).

        Ive now adjusted it down to 1.2 (max) and 10.3, and the two shots i pulled 10 mins ago were noticeably more consistent in colour & flow rate.

        oh well! its been a learning experience, and the coffee has actually been very good even with the settings being all wrong!
        Anytime skelly,

        When I used the prototype at Aromafest 2009, I had issues with the flow rate 20ml onwards as well. I know that ECA took that back to VBM and revisions for the Aussie market were made. I guess NZ is too small and you just get boxes at Euro spec....

        Most important thing though is that the shots have improved....Enjoy  8-)

        Chris

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        • #34
          Re: VBM Domobar Jr - ? burnt coffee

          Ok, So now I have the new grinder, Ive been trying to get my routine down pat, so I can reduce variables.

          So today I did a before and after weigh of the portafilter handle with and without coffee.

          With my double basket I am filling it with 22g of coffee - according to the electronic scales !!

          I was amazed, I thought it might come back at 18-20g.

          I know theres no right or wrong answer, and the coffee pours/extracts well and tastes great - I still cant believe the taste difference between the Mazzer Mini and the Sunbeam.

          Now that I know the dose, I want to micrometrically  ;D reduce my grind size a smidge to fine tune the extraction, altthough I find the adjuster very stiff on the Mini. Im assuming the grinder should be ON for any adjustments preferably with no coffee- is that right ? Also Ive been reading about duty cycle does that mean it shouldnt be on for more than 30 sec at a time and then remain off for 45 sec between grinds?

          Also, Im still not convinced about the doser - smoetimes I think it just gets in the way, and if I weigh my beans before going in eg 22g then I have to account for what I lose to the left and what gets left in the chamber - time for sweeper mod! Although my only other options were Mini-e for $400 more or Compak K3 touch. Anyway Ill get used to the doser - although I am realising it is more user friendly for the cafe/entertaining environment.

          BTW my milk texturing is now much better - its still a difficult wand to master - but Im getting there.

          Just some observations.

          Comment


          • #35
            Re: VBM Domobar Jr - ? burnt coffee

            Originally posted by 6E6962626978780C0 link=1267828746/33#33 date=1269038467
            Now that I know the dose, I want to micrometrically ;D reduce my grind size a smidge to fine tune the extraction, altthough I find the adjuster very stiff on the Mini. Im assuming the grinder should be ON for any adjustments preferably with no coffee- is that right ? Also Ive been reading about duty cycle does that mean it shouldnt be on for more than 30 sec at a time and then remain off for 45 sec between grinds?
            The grinder should be on for adjusting finer unless it is really empty. This avoids compressing grinds between the plates and possibly damaging something.

            Duty cycle: Yup -- youve got it. If you are "grinding on demand" this is no issue as a double will grind in way less than 30 seconds, and after you make that coffee and get back for another dose it should have adequately cooled.

            Dose: Use the 5-cent piece test to fine tune the VOLUME of the dose, and then the scales if you want to keep that consistent--Note that every change of bean or grind will change the volume, and it is the volume that is important, not the weight.

            Good to see its working for you.

            Greg

            Comment


            • #36
              Re: VBM Domobar Jr - ? burnt coffee

              Originally posted by 0F3A2D2F1F273A2529242C480 link=1267828746/34#34 date=1269053453
              Dose: Use the 5-cent piece test to fine tune the VOLUME of the dose, and then the scales if you want to keep that consistent--Note that every change of bean or grind will change the volume, and it is the volume that is important, not the weight.
              I sort of understand what youre saying. Once I change the grind or even the beans the same weight eg 22g of coffee will occupy a different volume in the basket hence affecting extraction. So overall volume is more important. Will try 5c test

              Comment


              • #37
                Re: VBM Domobar Jr - ? burnt coffee

                Originally posted by 53545F5F544545310 link=1267828746/35#35 date=1269056833
                Originally posted by 0F3A2D2F1F273A2529242C480 link=1267828746/34#34 date=1269053453
                Dose: Use the 5-cent piece test to fine tune the VOLUME of the dose, and then the scales if you want to keep that consistent--Note that every change of bean or grind will change the volume, and it is the volume that is important, not the weight.
                I sort of understand what youre saying. Once I change the grind or even the beans the same weight eg 22g of coffee will occupy a different volume in the basket hence affecting extraction. So overall volume is more important. Will try 5c test
                [smiley=thumbsup.gif]

                Let us know how you go.

                Greg

                Comment


                • #38
                  Re: VBM Domobar Jr - ? burnt coffee

                  hi bennett . My super leva delivers consistent burnt shots as well . I adjusted the pressure boiler and is now stagning at 0.5b climbing to 0.8b when it heats up. result is no more burnt coffee but less power when froth ing the milk . try that ..

                  Comment


                  • #39
                    Re: VBM Domobar Jr - ? burnt coffee

                    Originally posted by 43485249534C45524F49200 link=1267828746/37#37 date=1270193793
                    stagning at 0.5b climbing to 0.8b when it heats up
                    WOW, that would drastically alter steaming capabilities i would imagine!!

                    Cooling flushes never worked?

                    PS; they should

                    Comment


                    • #40
                      Re: VBM Domobar Jr - ? burnt coffee

                      Originally posted by 5853495248575E4954523B0 link=1267828746/37#37 date=1270193793
                      stagning at 0.5b climbing to 0.8b when it heats up
                      Thats really low, however if it tastes good maybe its correct.

                      My boiler pressure gauge varies between 1.2-1.4 bar. My brew pressure gauge consistently hits 10 bar during a shot.

                      My technique is now really consistent and I am not sure if the machine needs some minor tweaking/fine tuning or not. Because I am such an amateur I am not sure,  however I still think its slightly too hot.

                      Ive been meaning to call Renzo at Di Bartoli for some advice. I really dont want to take it all the way back to the shop unless I have to, my coffee tastes quite good, however its slightly bitter still and I am not sure if it needs tweaking. My beans are super fresh and Ive tried to minimise all other variables....

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                      • #41
                        Re: VBM Domobar Jr - ? burnt coffee

                        Im not actually being 100% correct.

                        After the machine does its warmup, the gauge sits between 1.2-1.25, which is meant to be spot on.

                        After a bit of use - eg shots and steaming - or when idle, it heats up and overshoots to about 1.4 and slowly comes down a bit.

                        I dont want to mess with the pressurestat, coz it could actually be spot on as it is, and me playing with it just stuffs it up.

                        Renzo bench tested it when I bought it, so it makes me even more reluctant to stuff around with it.

                        Although my gut feeling is that it needs to be brought down a tiny bit.

                        Comment


                        • #42
                          Re: VBM Domobar Jr - ? burnt coffee

                          Gday Bennett....

                          Seems to me mate, that you are approaching this the right way with your new machine. Involving your vendor is vital before making any changes otherwise it becomes very difficult to compare apples with apples when seeking their assistance with some problem you may be experiencing.

                          Its the way I would be doing things if I was in your place....

                          Mal.

                          Comment


                          • #43
                            Re: VBM Domobar Jr - ? burnt coffee

                            Originally posted by 2D263C273D222B3C21274E0 link=1267828746/37#37 date=1270193793
                            My super leva delivers consistent burnt shots as well . I adjusted the pressure boiler and is now stagning at 0.5b climbing to 0.8b when it heats up. result is no more burnt coffee but less power when froth ing the milk . try that ..
                            All what you done is reducing the amount of preasure in the boiler, which means let temperarure.

                            Originally posted by 2C2B20202B3A3A4E0 link=1267828746/40#40 date=1270200299
                            Im not actually being 100% correct.

                            After the machine does its warmup, the gauge sits between 1.2-1.25, which is meant to be spot on.

                            After a bit of use - eg shots and steaming - or when idle, it heats up and overshoots to about 1.4 and slowly comes down a bit.

                            I dont want to mess with the pressurestat, coz it could actually be spot on as it is, and me playing with it just stuffs it up.

                            Renzo bench tested it when I bought it, so it makes me even more reluctant to stuff around with it.

                            Although my gut feeling is that it needs to be brought down a tiny bit.
                            Bennet and Chriseroi, you are welcome to bring the machine and we can drop a bit preasure down a bit if you wish. You need to bring the beans that you are using to tested with different drops or hights

                            Bennet and Chriseroi have you try the cold flash, with different amount of flashing. Beacuse you have to remember different beans diffent flavours, different amount of flashing

                            Regads

                            Renzo
                            Di Bartoli Home Barista Centre

                            Any way give a call on tuesday to arrange time

                            Comment


                            • #44
                              Re: VBM Domobar Jr - ? burnt coffee

                              Originally posted by 507D4B567566607B787D140 link=1267828746/42#42 date=1270247112
                              Bennet and Chriseroi have you try the cold flash, with different amount of flashing
                              Hi Renzo, my machine is very close to being spot on - so as you suggested I have started playing with the amount of cold flushing to adjust temp, rather than adjust the pressurestat, and it makes a difference.

                              Although I might pop in just to say hi.  ;D

                              By the way, I got some beans from Hazel. Man shes a genius! Absolutely delicious.

                              Happy Easter.

                              Jerome

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                              • #45
                                Re: VBM Domobar Jr - ? burnt coffee

                                since i adjusted my pstat to the correct settings...

                                ive enjoyed huge improvement in consistency - no more early blonding!
                                cooling flushes are basically unnecessary
                                dont have as much steam power as before, of course, but its still enough

                                ive been noticing slight pressure increases sometimes.. maybe due to warmer weather? or the volume of water in the resovior? not really an issue though..

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