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Thread: Cooling Flush On A VBM Domobar Jnr?

  1. #1
    JJJ
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    Cooling Flush On A VBM Domobar Jnr?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Ive seen quite a lot of discussion about cooling flushes on the Domobar Jnr, with many suggesting it generally needs only a quick flush (if at all).

    However, im finding with mine that it needs a seemingly inordinate amount of time for the water to form a single, smooth flow (as one expects from a pour with a naked group).

    Generally it hisses for about 5-6 seconds before turning into numerous streams of water which slowly settle, however it takes at least 30-40 seconds before those streams come together and form one solid, smooth flow (if at all).

    I assume thats way too long? If it is, what can i do to address the issue?

    I thought about trying to borrow a temp data logger (i so need to buy one) and measuring the water temperature to accurately discover exactly when in the cooling flush process i reach the ideal brewing temperature, but that aside im at a loss.

    Im not really happy with what my machine is producing, although im generally not experiencing the telltale signs of a excessive brew temp (that being a defined sourness).

    BTW The machine is about 15-16 months old and was calibrated on the day of purchase.

    Thanks in advance, lads.
    Ristrom

  2. #2
    TC
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    Re: Cooling Flush On A VBM Domobar Jnr?

    Hello Ristrom,

    If you can hear prolonged steam during the rinse, then its too hot. You may not neccessarily see a single stream as that can be dictated by the anatomy of the dispersion screen as well as that of the shower screen.

    If its running too hot, youd be getting bitter (burned) rather than sour.

    My advice would be to run it beside a demo machine known to be operating well- with the same grinder and coffee and then to log it using a Scace II device if required.

    Good luck!

    Chris

  3. #3
    JJJ
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    Re: Cooling Flush On A VBM Domobar Jnr?

    Quote Originally Posted by 7D484542766A464F4F4C4C290 link=1320643330/1#1 date=1320644189
    If you can hear prolonged steam during the rinse, then its too hot.
    Ive been so focused on the visual that i havent even noticed the sound its making.
    Will focus entirely on the sound with my next shot and see how long it takes for the sound of steam to dissipate.

    Quote Originally Posted by 7D484542766A464F4F4C4C290 link=1320643330/1#1 date=1320644189
    You may not neccessarily see a single stream as that can be dictated by the anatomy of the dispersion screen as well as that of the shower screen.
    Ah, that i did not know (but probably should have).
    Unless the machine has been used a few times in a short period (or just finished back flushing) i dont really see a single stream during the cooling flush, instead it generally settles into four evenly distributed streams.

    Quote Originally Posted by 7D484542766A464F4F4C4C290 link=1320643330/1#1 date=1320644189
    My advice would be to run it beside a demo machine known to be operating well- with the same grinder and coffee and then to log it using a Scace II device if required.
    That would require another visit to your fine establishment at some point, Chris.

    As i said in the OP, im not really happy with my results in recent months but its so difficult to pinpoint the problem.
    Ive tried varying my dose, changing baskets, varying my grind settings and numerous other things but alas, no major improvement, yet.

    You probably told me upon purchasing but how often should one have such a machine serviced?

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    TC
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    Re: Cooling Flush On A VBM Domobar Jnr?

    Quote Originally Posted by 5F5F5F150 link=1320643330/2#2 date=1320646096
    instead it generally settles into four evenly distributed streams.
    Sounds pretty normal to me...

    Quote Originally Posted by 5F5F5F150 link=1320643330/2#2 date=1320646096
    That would require another visit to your fine establishment at some point, Chris.
    Youre always welcome. Just try to keep your eyes averted from the demo bench!* ;D

    Quote Originally Posted by 5F5F5F150 link=1320643330/2#2 date=1320646096
    You probably told me upon purchasing but how often should one have such a machine serviced?
    We should probably have had a chat 3-4 months ago. Id think its most likely due for a group seal and perhaps a shower screen as well...

    Drop me a line if you want to make a time to come in.

    C

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    Senior Member bennett's Avatar
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    Re: Cooling Flush On A VBM Domobar Jnr?

    I go through periods where my results arent as good as normal and I swear the machine must be running hot. However most of the time its my technique or the beans or the grinder at fault.

    A few weeks ago I was getting ordinary results from a particular blend which I hadnt used before from a reputable Sydney supplier. I was really frustrated. Next batch I bought some beans from Talk coffee and I have been making amazing coffee for the last 2 weeks. Thanks Chris* ;D

    A few months ago, whatever I did the coffee just wasnt right. I thought it was the VBM. Then I stripped my mazzer clean - instantly amazing results.

    My point is, there are so many variables - grinder, beans, barista the machine is very rarely at fault. It is human nature to worry about the machine - and it may well need a bit of TLC, but chances are something else is at fault. Are you home roasting? Have u tried buying some brown beans to see if that is the problem?

    By the way, you would notice if it was running hot - it would hiss and puff like an old steam train. Hope this helps.

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    JJJ
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    Re: Cooling Flush On A VBM Domobar Jnr?

    Thanks for the reply, bennett.
    Its really disheartening when you go through a rough patch with your coffee, especially when you cant pinpoint the problem.

    Quote Originally Posted by 5E5952525948483C0 link=1320643330/4#4 date=1320654032
    Then I stripped my mazzer clean - instantly amazing results.
    That could actually be an issue with me because ive had some grief when it comes to cleaning my K3T.

    Its horribly embarrassing but i simply cannot take it apart despite reading the manual numerous times and reading countless threads on the matter.

    On top of that, the last 4-5 times ive used Grindz its choked the grinder to the point where its inoperable until i take the hopper off and find a way to dislodge the stuck Grindz.

    As i said, incredibly embarrassing and it leaves my only real cleaning option to take off the hopper, clean it and vacuum the exposed areas.

    EDIT: Ive finally had success in taking apart the grinder (the photo in the manual suggests you remove the three black screws for some reason, but you dont actually even touch them).
    Ill give it a real clean tonight and see if that makes a difference (im sure it will).
    Still doesnt solve the Grindz issue, but its a great start.
    Thanks for the suggestion, bennett.

    Quote Originally Posted by 5E5952525948483C0 link=1320643330/4#4 date=1320654032
    Are you home roasting? Have u tried buying some brown beans to see if that is the problem?
    I do roast at home, yes, but once a month or so i run some beans from some of the best roasters in the land (and sometimes overseas) through it, so i dont think its the beans.

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    Re: Cooling Flush On A VBM Domobar Jnr?

    Hi Ristrom

    To get into the K3T:

    Unplug from wall. Remove the silver cover and the screw under it - its only there to stop you turning the adjustment too far. Now just adjust the grinder to a larger grind size, but keep turning until the top burr carrier is off. Oggle at the crusty buildup and clean. Thread the carrier back the other way until you hit the lower burr, back it off a bit (id back my one off by about 5) then test with beans and adjust like normal - dont run it dry. Easy.

    Cheers
    Andrew

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    JJJ
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    Re: Cooling Flush On A VBM Domobar Jnr?

    Quote Originally Posted by 785E496844455F594A485F44592B0 link=1320643330/6#6 date=1320659531
    Easy.
    It certainly is once you know how to do it.
    Theres an incredible amount of built up grounds in there and theyre quite difficult to move, but i guess i had to expect that given how long its been without the burrs being cleaned.

    Quote Originally Posted by 785E496844455F594A485F44592B0 link=1320643330/6#6 date=1320659531
    Thread the carrier back the other way until you hit the lower burr, back it off a bit (id back my one off by about 5) then test with beans and adjust like normal - dont run it dry.
    Thanks for the tip, the manual is a bit vague about where to stop when refitting the top burr so ill try to follow your suggestion.

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    TC
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    Re: Cooling Flush On A VBM Domobar Jnr?

    Quote Originally Posted by 0505054F0 link=1320643330/5#5 date=1320658917
    EDIT: Ive finally had success in taking apart the grinder (the photo in the manual suggests you remove the three black screws for some reason, but you dont actually even touch them).
    You actually almost always do as there is a stop screw which will prevent travel of the collar. Seems its been removed in your case.

    Quote Originally Posted by 0505054F0 link=1320643330/5#5 date=1320658917
    Still doesnt solve the Grindz issue, but its a great start.
    You need to set your grinder to super coarse to use Grindz or it either chokes or does nothing ;-)




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