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Thread: Bezzera Domus Galatea pressure

  1. #1
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    Bezzera Domus Galatea pressure

    Cafelat Coffee Tamper and Accessories
    hello. I have just brought a Bezzera Domus Galatea and have managed to make a drinkable latte but espresso undrinkable without equal parts sugar! Pump pressure is just over 12 bar. Is this adjustable or does it need to be adjusted by service team?

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    Senior Member Lovey's Avatar
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    Re: Bezzera Domus Galatea pressure

    Gday Ballarat Bob, welcome to CS.
    Is your machine the plumb in version or the tank version?

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    Re: Bezzera Domus Galatea pressure

    pressure could be adjusted down a tad to around 9 or 10 bar. Although the coffee shouldnt be "undrinkable" at 12 bar. It could be a problem with your barista skills, your grinder, your beans, your water etc etc ( you get the point) but in any case youll probably get better coffee if the pressure is reduced slightly :)

  4. #4
    Senior Member Koffee_Kosmo's Avatar
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    Re: Bezzera Domus Galatea pressure

    Quote Originally Posted by 5E434E4F4D5A2C0 link=1306324644/0#0 date=1306324644
    hello. I have just brought a Bezzera Domus Galatea and have managed to make a drinkable latte but espresso undrinkable without equal parts sugar! Pump pressure is just over 12 bar. Is this adjustable or does it need to be adjusted by service team?*

    A lot of people do not understand much on what is bar pressure

    An OPV (over pressure valve) is a safety release valve designed to redirect water to the water tray so your machine operates within a margin of its rated safety limits

    Picture this
    You grind course and tamp light

    You pull a shot and its a gusher
    You say it must be the bar pressure ?? not so
    The bar pressure only comes into play when it actually reaches the set amount

    In the above scenario the pressure would have been about 2 to 5 bar

    Even if you set the bar pressure @ 9 bar you will get the same result

    Its more important that you need to work on your grind, dose & tamp depth
    This in conjunction with fresh beans

    One other simple explanation is that your taste pallet may not be used to it (straight espresso coffee)
    Or if you are using a blend it may contain the stronger tasting Robusta

    This is a video of the Galatea that I owned
    Its set at 12 bar

    [media]http://www.youtube.com/watch?v=tkWjQnLJ6-E[/media]

    KK




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    Re: Bezzera Domus Galatea pressure

    Quote Originally Posted by 67434A4A49497367435F41432C0 link=1306324644/3#3 date=1306374762
    An OPV (over pressure valve) is a safety release valve designed to redirect water to the water tray so your machine operates within a margin of its rated safety limits

    No, the OPV that comes after a vibrating pump is not for safety, its to give a degree of adjustability to a pump which is not adjustable.


    Quote Originally Posted by 745059595A5A6074504C52503F0 link=1306324644/3#3 date=1306374762
    A lot of people do not understand much on what is bar pressure
    you included

  6. #6
    Senior Member Koffee_Kosmo's Avatar
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    Re: Bezzera Domus Galatea pressure

    Quote Originally Posted by 62465C4C474E2F0 link=1306324644/4#4 date=1306377362
    No, the OPV that comes after a vibrating pump is not for safety, its to give a degree of adjustability to a pump which is not adjustable.
    And if the OPV does not have a set release of pressure point the pump will be damaged or blow at at any weakest point in that line* *
    Its also possible to have an electrical overload

    If thats not a safety feature that I will eat my hat

    Would you like me to explain the correlation of the puck and water under pressure

    However before I do, please explain your knowledge

    KK

  7. #7
    brett230873
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    Re: Bezzera Domus Galatea pressure

    Quote Originally Posted by 01253F2F242D4C0 link=1306324644/4#4 date=1306377362
    Quote Originally Posted by 67434A4A49497367435F41432C0 link=1306324644/3#3 date=1306374762
    An OPV (over pressure valve) is a safety release valve designed to redirect water to the water tray so your machine operates within a margin of its rated safety limits

    No, the OPV that comes after a vibrating pump is not for safety, its to give a degree of adjustability to a pump which is not adjustable.


    Quote Originally Posted by 745059595A5A6074504C52503F0 link=1306324644/3#3 date=1306374762
    A lot of people do not understand much on what is bar pressure
    you included
    ;D ;D ;D Me either for that matter. Now who wants to explain it properly?

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    Re: Bezzera Domus Galatea pressure

    This seems like a good time and place to ask a serious question about pump pressure and opv function.
    With a pump such as the ulka ep5, I recall it will deliver about 90ml water in 30 sec at 9bar. If the opv is set at 12bar, and grind/dose/tamp control the flow, you either get* a 20 sec extraction (for double) or* approx 10.5 bar exteaction for 30sec, unless some water magically disappears.

    Am I missing something obvious?

    Edit: one thing occurred to me as soon as I posted but lets see what other thoughts there are before I expose my stupidity any further.

  9. #9
    brett230873
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    Re: Bezzera Domus Galatea pressure

    Quote Originally Posted by 51756F7F747D1C0 link=1306324644/4#4 date=1306377362
    Koffee Kosmo wrote Today at 11:52am:

    An OPV (over pressure valve) is a safety release valve designed to redirect water to the water tray so your machine operates within a margin of its rated safety limits


    No, the OPV that comes after a vibrating pump is not for safety, its to give a degree of adjustability to a pump which is not adjustable.
    Mischa, that is an intensly useful and no-nonsense description. Thank you! I appreciate KKs attempts to explain also but alas my Masters Degree was in Music ::) so I didnt quite follow. Better punctuation and syntax may have assisted me in understaning his thoughts but then again, perhaps not.

  10. #10
    Site Sponsor Di_Bartoli's Avatar
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    Re: Bezzera Domus Galatea pressure

    Hi guys I found this, it may help to explain how the Over Pressure Valve works

    http://www.espressomyespresso.com/

    If you go to: How a Pressure Relief Valve Works and click here you will see.

    Going back to the original question, of 12 bars which if you Scase II this machine probably will be only 10.5 bars due to that the gauges are not 100% accrued.*

    What I would look at* is the coffee as well as the pump pressure, some coffees are good for espresso and milk others are good as espresso only.* making coffee is about variables, we should look at one variable at a time*

    * Machine
    * Grinder (Fine or Coarse)
    * Beans
    * Your self (your routine)

    But what do I know anyway?!?

    Regards


    Renzo

  11. #11
    Senior Member Koffee_Kosmo's Avatar
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    Re: Bezzera Domus Galatea pressure

    Quote Originally Posted by 2D252B23213B3B272B23480 link=1306324644/7#7 date=1306381626
    This seems like a good time and place to ask a serious question about pump pressure and opv function.
    With a pump such as the ulka ep5, I recall it will deliver about 90ml water in 30 sec at 9bar. If the opv is set at 12bar, and grind/dose/tamp control the flow, you either get* a 20 sec extraction (for double) or* approx 10.5 bar exteaction for 30sec, unless some water magically disappears.

    Am I missing something obvious?

    Edit: one thing occurred to me as soon as I posted* but lets see what other thoughts there are before I expose my stupidity any further.
    Lets see
    A stated free flow on a pump is XYZ
    This is also based on the full pressure that the pump is rated at XYZ

    When you place a restrictor in its path the water volume flow will be slower

    A common household item that is a restrictor is a water saving shower head*

    KK

  12. #12
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    Re: Bezzera Domus Galatea pressure

    Sorry the website that I was referring is this:

    http://www.espressomyespresso.com/

    You will find all the information here

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    Re: Bezzera Domus Galatea pressure

    Renzo link not displaying so just go to www.espressomyespresso.com

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    Re: Bezzera Domus Galatea pressure

    Sorry Renzo link is not displaying but you will find information in espresso my espresso (all one word) .com etc. picture will tell a thousand words

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    Re: Bezzera Domus Galatea pressure

    Thanks for all your comments guys, they have been helpfull. I dont doubt for a minute my inexperience is most ( if not all) of the problem. I went to the Bezzera dealer in Geelong today and very impressed by his effort to explain possible issues I am experiencing, and got some excellent advice regarding my machine. Brought 2 different types of beans to experiement with and look forward to palying with my new "toy". Cheers

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    Re: Bezzera Domus Galatea pressure

    Quote Originally Posted by 2B0F060605053F2B0F130D0F600 link=1306324644/5#5 date=1306378629
    Quote Originally Posted by 62465C4C474E2F0 link=1306324644/4#4 date=1306377362
    No, the OPV that comes after a vibrating pump is not for safety, its to give a degree of adjustability to a pump which is not adjustable.
    And if the OPV does not have a set release of pressure point the pump will be damaged or blow at at any weakest point in that line* *
    Its also possible to have an electrical overload

    If thats not a safety feature that I will eat my hat

    Would you like me to explain the correlation of the puck and water under pressure

    However before I do, please explain your knowledge

    KK

    Actually, a pump running at higher pressure and lower flow rate consumes LESS power than one running at full flow with less pressure.

    The pump will not be damaged if it runs at full pressure with no flow. It will simply be pushing water around inside its own housing.

    The piping is all designed to withstand the pressure the pump can produce, plus a factor of safety. So it can probably handle at least double the pumps max pressure.

    I can promise you that the ovp is simply an adjustability thing.

    My knowledge? is a mechanical engineering degree sufficient?* ;)

    Also, have you considered what would happen if the pump happened to blow a hose off? You would hear a tiny "pop" sound and there would be a bit of cold water dripping out of the machine... hardly catastrophic.

  17. #17
    brett230873
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    Re: Bezzera Domus Galatea pressure

    Quote Originally Posted by 15312B3B3039580 link=1306324644/15#15 date=1306456252
    Quote Originally Posted by 2B0F060605053F2B0F130D0F600 link=1306324644/5#5 date=1306378629
    Quote Originally Posted by 62465C4C474E2F0 link=1306324644/4#4 date=1306377362
    No, the OPV that comes after a vibrating pump is not for safety, its to give a degree of adjustability to a pump which is not adjustable.
    And if the OPV does not have a set release of pressure point the pump will be damaged or blow at at any weakest point in that line* *
    Its also possible to have an electrical overload

    If thats not a safety feature that I will eat my hat

    Would you like me to explain the correlation of the puck and water under pressure

    However before I do, please explain your knowledge

    KK

    Actually, a pump running at higher pressure and lower flow rate consumes LESS power than one running at full flow with less pressure.

    The pump will not be damaged if it runs at full pressure with no flow. It will simply be pushing water around inside its own housing.

    The piping is all designed to withstand the pressure the pump can produce, plus a factor of safety. So it can probably handle at least double the pumps max pressure.

    I can promise you that the ovp is simply an adjustability thing.

    My knowledge? is a mechanical engineering degree sufficient?* ;)

    Also, have you considered what would happen if the pump happened to blow a hose off? You would hear a tiny "pop" sound and there would be a bit of cold water dripping out of the machine... hardly catastrophic.
    Brilliant! Thanks Mischa!

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    Re: Bezzera Domus Galatea pressure

    oh and an ovp is not a restrictor. Its a VALVE. it diverts water out of the stream to bleed off pressure

  19. #19
    Senior Member Koffee_Kosmo's Avatar
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    Re: Bezzera Domus Galatea pressure

    Your explanation is no different than mine
    Just worded differently

    I simply said that an OPV its a safety device (and it is)
    I also said that its a release valve designed to redirect water to the water tray (and it is)

    Should I have also added that some units are adjustable and some are static
    No as I did not want to complicate the matter for the OP

    The portion of my post you quoted was only 3 lines out of many and the rest of the post gives other possibilities

    Quote Originally Posted by 66425848434A2B0 link=1306324644/17#17 date=1306456575
    oh and an ovp is not a restrictor. Its a VALVE. it diverts water out of the stream to bleed off pressure
    This is correct
    I dont see anywhere where I said in the same sentence that the OPV is a restrictor

    KK


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    Re: Bezzera Domus Galatea pressure

    so if its a safety valve, please tell me what exactly is it protecting us from??

    gotta love internet forums, everyone is an expert

  21. #21
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    Re: Bezzera Domus Galatea pressure

    Easy guys, youre actually saying the same thing. Its just semantics.

    Bottom line is its entirely possible to get a great shot at 12 bar (perhaps more like 10.5 actual?). If anything, it may need to be restricted a little. Why some DG machines are so difficult to adjust and why they produce the 9 bar scream is a different matter ::)

    The issue with the OPs machine is more likely related to bean age, grind, dose and possibly tamp.

    To get any real sense of what its doing, it needs to spend time with a Scace 2.

    Chris

  22. #22
    Senior Member Koffee_Kosmo's Avatar
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    Re: Bezzera Domus Galatea pressure

    Quote Originally Posted by 0E2A30202B22430 link=1306324644/19#19 date=1306485867
    so if its a safety valve, please tell me what exactly is it protecting us from??

    gotta love internet forums, everyone is an expert
    I have been a Mechanical Engineer for 38 years
    And I dont profess that I am an expert as I have never stopped learning

    Do me a favour and google to verify that an OPV does act as a safety mechanism
    For its intended design it primarily protects the the equipment that its fitted on to

    Quote Originally Posted by 17222F281C002C25252626430 link=1306324644/20#20 date=1306486562
    Easy guys, youre actually saying the same thing. Its just semantics.

    Bottom line is its entirely possible to get a great shot at 12 bar (perhaps more like 10.5 actual?). If anything, it may need to be restricted a little. Why some DG machines are so difficult to adjust and why they produce the 9 bar scream is a different matter Roll Eyes
    Thank you Chris
    Glad someone can see its the same thing said in differing ways
    I am assuming you have read my original post

    Quote Originally Posted by 17222F281C002C25252626430 link=1306324644/20#20 date=1306486562
    The issue with the OPs machine is more likely related to bean age, grind, dose and possibly tamp.


    Chris
    Again thats exactly what I said on my first post

    KK

  23. #23
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    Re: Bezzera Domus Galatea pressure

    Quote Originally Posted by 77534959525B3A0 link=1306324644/15#15 date=1306456252
    The pump will not be damaged if it runs at full pressure with no flow. It will simply be pushing water around inside its own housing.
    For a short time, sure....

    Wouldnt want it going on for too long though, as heat generated by friction can be enough to boil the water trapped within the pump casing and then cause the pump to run dry.... Not a good thing :(

    Mal.

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