Results 1 to 4 of 4
Like Tree4Likes
  • 1 Post By Dimal
  • 2 Post By MrJack
  • 1 Post By gazza

Thread: How do you measure brew pressure for OPV adjustment?

  1. #1
    Senior Member
    Join Date
    Jul 2013
    Posts
    122

    How do you measure brew pressure for OPV adjustment?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi guys,

    I am currently in the process of adjusting the OPV in my e61 HX machine to get the optimal 9bar brew pressure. the machine gives me > 12bar peak from the factory which is on the high side.

    I know in order to get 9 bar at the brew head I will need to get 10bar at the pressure gauge. but the thing I am not sure of is how do you measure the 10bar, I had adjusted the OPV to get around 10.5bar at the gauge by using a blind disc in the PF. however when I actually make a coffee the reading is a bit lower (<9 bar).

    Can someone shed some light on this?

    Cheers.

  2. #2
    Mal Dimal's Avatar
    Join Date
    Oct 2004
    Location
    Warwick, QLD
    Posts
    16,772
    Sounds close to perfect mate....

    No need to muck around any further...

    Mal.
    symphonie likes this.

  3. #3
    Senior Member
    Join Date
    Oct 2011
    Posts
    1,376
    Quote Originally Posted by symphonie View Post
    Hi guys,

    I am currently in the process of adjusting the OPV in my e61 HX machine to get the optimal 9bar brew pressure. the machine gives me > 12bar peak from the factory which is on the high side.

    I know in order to get 9 bar at the brew head I will need to get 10bar at the pressure gauge. but the thing I am not sure of is how do you measure the 10bar, I had adjusted the OPV to get around 10.5bar at the gauge by using a blind disc in the PF. however when I actually make a coffee the reading is a bit lower (<9 bar).

    Can someone shed some light on this?

    Cheers.
    One way of looking at it:

    When you have the blind in, there is no flow to the group. The pressure at the pump discharge is limited by the OPV, and the pressure at the group will be the same.

    When there is no blind in, there is flow through the group. When the water is flowing, it drags along the pipe wall, losing energy to it. This manifests as "pressure drop" (meaning the pressure at the outlet of the pipe is lower than at the inlet.
    Dimal and sprezzatura like this.

  4. #4
    Senior Member
    Join Date
    Jan 2009
    Location
    ACT
    Posts
    154
    Behmor Brazen - $249 - Free Freight
    I think Greg's portafilter with a pressure gauge is still available, check this thread:

    http://coffeesnobs.com.au/brewing-equipment-non-machine-specific/36501-greg-pullmans-portafilter-pressure-gauge-road.html


    Gary
    Dimal likes this.



Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •