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Thread: Vibiemme Domobar Super Manual

  1. #1
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    Vibiemme Domobar Super Manual

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    Just bought a new Vibiemme and having a lot of fun experimenting. I’m going through coffee like it’s going out of style. I noticed the brew pressure was up around 13 bar. The manual states that the pump pressure should be 9 bar ±1 bar. Later it talks of an optimum brew pressure of 8.6 to 9.2 bar. Anyway, it seemed to me that one was supposed to adjust the grind and tamp to achieve that brew pressure. Try as I may I couldn’t do it. The brews were either bitter or sour. The next step was to attack the pressure relieving valve (PRV). It took about ¾ of a turn to get the brew pressure to around 9 bar. There was a better balance between bitter and sour and neither was too distinctive. Did I do the right thing? Has anyone experimented with this? It seems incongruous to me that they recommend 9 bar then supply the machine with the PRV set to 13 bar. I’ve since read that it’s not unusual for machines to be delivered with the PRV turned right up. I’ve also read that there might be about 1 bar head loss in the system so it might be better to set the PRV to 10 bar. With the large diameter plumbing and the low flow rates, I wouldn’t have thought the losses to be that high. What do people think? Does it matter much anyway?

    Another thing, in drawing a brew, do people hesitate half way to get the pre-infusion? If so, how long? The manual makes no mention of it.

    By the way, where do these guys get their manual writers from? They wouldn’t pass junior high English here. Work this out, “When coffee starts going out from handled, look at pressure gauge, the perfect diffusion screen is when the pressure gauge indicates between 8,6/9,2 bar. If the value is higher it means that coffee is too dense while if it is lower means coffee has been ground too much thin.”

  2. #2
    TC
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    Re: Vibiemme Domobar Super Manual

    Quote Originally Posted by BobT link=1218946999/0#0 date=1218946998
    Just bought a new Vibiemme and having a lot of fun experimenting. *I’m going through coffee like it’s going out of style. *I noticed the brew pressure was up around 13 bar. *The manual states that the pump pressure should be 9 bar ±1 bar. *Later it talks of an optimum brew pressure of 8.6 to 9.2 bar. *Anyway, it seemed to me that one was supposed to adjust the grind and tamp to achieve that brew pressure. *Try as I may I couldn’t do it. *The brews were either bitter or sour. *The next step was to attack the pressure relieving valve (PRV). *It took about ¾ of a turn to get the brew pressure to around 9 bar. *There was a better balance between bitter and sour and neither was too distinctive. *Did I do the right thing? *Has anyone experimented with this? *It seems incongruous to me that they recommend 9 bar then supply the machine with the PRV set to 13 bar. *I’ve since read that it’s not unusual for machines to be delivered with the PRV turned right up. *I’ve also read that there might be about 1 bar head loss in the system so it might be better to set the PRV to 10 bar. *With the large diameter plumbing and the low flow rates, I wouldn’t have thought the losses to be that high. *What do people think? *Does it matter much anyway?

    Another thing, in drawing a brew, do people hesitate half way to get the pre-infusion? *If so, how long? *The manual makes no mention of it.

    By the way, where do these guys get their manual writers from? *They wouldn’t pass junior high English here. *Work this out, “When coffee starts going out from handled, look at pressure gauge, the perfect diffusion screen is when the pressure gauge indicates between 8,6/9,2 bar. *If the value is higher it means that coffee is too dense while if it is lower means coffee has been ground too much thin.”
    Hi Bob,

    Hopefully your supplier used a portafilter pressure gauge and set the OPV to 9 bar at the group. This is a component of our bench test .

    The pressure gauge on your machine is a system pressure gauge and will typically read up to 1.0-1.5 bar higher than group pressure (with a blind filter in place).

    If it wasnt set, you might ask your supplier to do the job so that you have an accurate indication. ;)

    Chris

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    Re: Vibiemme Domobar Super Manual

    Thanks for the advice Chris. I got my own pressure gauge today and set the PF pressure to 9 bar. Ill see how it goes. And, yes, the difference between the PF gauge and the machines brew pressure gauge is about 1.0 bar on my machine. Im perplexed that Vibiemme recommend 8.6-9.2 bar as measured on the machines gauge. Are they then suggesting a PF pressure of between 7.6 to 8.2 bar?

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    Re: Vibiemme Domobar Super Manual

    Quote Originally Posted by BobT link=1218946999/0#2 date=1219043214
    Thanks for the advice Chris. *I got my own pressure gauge today and set the PF pressure to 9 bar. *Ill see how it goes. *And, yes, the difference between the PF gauge and the machines brew pressure gauge is about 1.0 bar on my machine. *Im perplexed that Vibiemme recommend 8.6-9.2 bar as measured on the machines gauge. *Are they then suggesting a PF pressure of between 7.6 to 8.2 bar?
    Good stuff Bob- this should make things a whole heap better!

    It perplexes me that so many companies will supply machines at 12 or more bar at the group and yet we all know that the sweet spot is around 9 bar. Then we get stories from some companies that its related to the vibe pump- and yet its the same as the pump in other machines which do ship at 9 bar?

    At least the VBM is easily adjusted. Better still, all Australian Giottos are coming to us set to 9 bar. I understand that this happens when ECA do their pre-shipment check. Kudos ECA!

    I guess its a good thing for CSers to check that their machines are calibrated correctly. Sadly, too many vendors just shift boxes and dont care too much about whats in the cup....

    I hope you enjoy a better brew now Bob ;)

    Chris



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