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Thread: The right (group) water temperature?

  1. #1
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    The right (group) water temperature?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi folks.
    My test results using Styro cup with thermometer and digital electronic temp measuring. SB EM7000 machine.

    Method
    (1) allow EM7000 to heat for 5 minutes prior to preheat of 1 cup through empty filter and group handle, pause 30 secs, 1 cup into styro cup and measure
    (2) no filter or handle, just group head with same preheat method and test method
    Peaks in the cup of:
    1= 59C
    2=65C
    This seems way too low; from what Ive read it should be minimum 80C to about 93C mean.
    Any advice appreciated; I know this machine lets me tweak the temperature but these results if I am correct, are way out of kilter?
    Thanks kindly, Alistair.

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    Even though I searched, I did not get this until after the post sorry about that!
    http://coffeesnobs.com.au/brewing-equipment-non-machine-specific/16199-water-temp-coming-out-group-head.html

    So mine still looks too far out though at 60C there is 20C difference.

  3. #3
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    Quote Originally Posted by BigalG View Post
    Even though I searched, I did not get this until after the post sorry about that!
    http://coffeesnobs.com.au/brewing-equipment-non-machine-specific/16199-water-temp-coming-out-group-head.html

    So mine still looks too far out though at 60C there is 20C difference.
    Hi Alistair

    Thanks, you just added one more "meaningless issue myth" which is too common on forums like this. I just emailed two others in an email the other day to a friend (wetness on the top of a puck & quantity of crema being the other two - so easy to rig and / or mislead).

    As the link you found suggested, even coming up with a methodology which is close enough to measure actual / real group temp is tricky. PIDs are really only a differentiating piece of educated guesswork. Embedding a sensor in the portafilter gets you closer, however the lag in most measuring gear makes even that problematic. Even my so-called "instant reading" medical thermo isn't really... and remember, the test gear has to be comfortable and accurate at 9+ bar as well... not found under too many XMas trees...

    As long as you are getting good coffee, it is irrelevant anyway.

    Good Extraction, Good Espresso - Espresso Guide • Home-Barista.com plus the next two "pages" shows you how to work it out via taste. Then you can set the temp in either direction on your 7000 and work out whether it is faulty or within range. By the time you have worked through that lot you will be able to taste the difference anyway. FWIW, my guess is "within range" as 60 degrees could not make anything like an espresso coffee (or even something beyond pig swill).

    Hope this helps


    TampIt

  4. #4
    Super Moderator Javaphile's Avatar
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    It helps if you let your machine warm up completely. 5 minutes is way to short a time for complete warming.


    Java "Good coffee is a process, not a shortcut" phile
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    Senior Member LeroyC's Avatar
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    Even though the instructions probably say that a 5min warm up is sufficient, I can assure you that it's not. I'd be aiming for about a 15min warm up, then test your temperatures by tasting the coffee.

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    Thanks coffee lovers.

    I followed the post I referred to (found after OP) and therein is a method whereby you heat a cup up to boiling in a microwave and then quickly take its temperature to calibrate your temperature device to 100C. Then you pour said boiling water from same height as group head into styro container, remeasure and using that difference + heat losses approximation in group head, you can come out a bit more accurately.
    Mine came out as a 20C difference which makes it pretty close to whats needed.

    Back to tasting the coffee...............

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    Quote Originally Posted by BigalG View Post
    Thanks coffee lovers.

    I followed the post I referred to (found after OP) and therein is a method whereby you heat a cup up to boiling in a microwave and then quickly take its temperature to calibrate your temperature device to 100C.
    It would be more accurate to bring a pot of water to boil over the stove and measure the temperature as it's boiling.

  8. #8
    Member dan110024's Avatar
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    Quote Originally Posted by TampIt View Post
    As the link you found suggested, even coming up with a methodology which is close enough to measure actual / real group temp is tricky. PIDs are really only a differentiating piece of educated guesswork. Embedding a sensor in the portafilter gets you closer, however the lag in most measuring gear makes even that problematic. Even my so-called "instant reading" medical thermo isn't really
    The best, fastest reading probes are the k-type thermocouples with the bare wire at the end (no solid probe). With such small thermal mass, they're pretty much instant. Almost too fast for some applications. You could carefully hold the end of it within the water coming through the spout of the portafilter or even stick it up there.


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    CoffeeSnobs Owner Andy's Avatar
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    Quote Originally Posted by BigalG View Post
    Thanks coffee lovers.

    I followed the post I referred to (found after OP) and therein is a method whereby you heat a cup up to boiling in a microwave and then quickly take its temperature to calibrate your temperature device to 100C. Then you pour said boiling water from same height as group head into styro container, remeasure and using that difference + heat losses approximation in group head, you can come out a bit more accurately.
    Mine came out as a 20C difference which makes it pretty close to whats needed.
    Total waste of time doing it this way to be honest....

    All you need to do with the afore-mentioned bead t/couple, is to prepare an espresso shot as you normally would, tamp down, etc and then feed the bead t/c over the lip of the filter basket as you lock the Group Handle into place, quite firmly to ensure there is a good seal around the t/c cable (won't do any harm to the cable or the Group Gasket). Just need to ensure that the bead itself is located about halfway between the centre of the puck and the basket rim just before locking in, to ensure that it receives a decent flush of the brew water.

    After your machine has warmed up for sufficient time, pull a shot as you normally would while the t/c is connected to your DMM, and record the temperatures being indicated while the shot is poured over the requisite 30s or so. Even better, if you have one of the CS Roast Monitor DMMs, you can use the Roast Monitor software to record the entire profile of the shot for closer examination later. This process can be repeated several times with the same puck in place before the flow rate starts to become excessive and a new espresso shot prepared. One episode is usually enough though for at least three to four recordings, and should be plenty.

    Mal.
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  11. #11
    Member dan110024's Avatar
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    Quote Originally Posted by Dimal View Post
    Even better, if you have one of the CS Roast Monitor DMMs, you can use the Roast Monitor software to record the entire profile of the shot for closer examination later.

    Multi-use Roast Monitor! I've even contemplated using it to log the temperature of a chilled water pipe at work That is until I thought I should stop being tight and bought an actual temperature logging device.
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  12. #12
    Mal Dimal's Avatar
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    Behmor Brazen - $249 - Free Freight
    I hope it use pt100/1000 sensors rather than t/couples though...

    Mal.
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