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Thread: Timing of shot pours

  1. #1
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    Timing of shot pours

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    When timing the shots from Silvia I have noticed a variation in the time it takes from first starting the pump to the time for first signs of coffee coming out of the pf spouts.

    Sometimes it is around the 4 seconds that seems to be "normal" (if there is such a thing).
    Sometimes it is closer to 6 or 7 seconds.

    Once it was a lot longer, but then I realised I had been steaming milk and not re-filled the boiler before I pulled the second shot so I put it down to that.

    So Im thinking that as I dont always run water through the pf prior to loading, because I have thermo probe attached to the boiler and dont need to temp surf, that its just relative boiler level.

    Can anyone shed some light on this please?

  2. #2
    Mal Dimal's Avatar
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    Re: Timing of shot pours

    Hi Bullitt,

    Yep, I think that is all it is..... relative Boiler level from one session to another. Ive noticed the same phenomenon with my Mokita since using it with PID. Ive just got into the habit of finishing off every session with a final flush-out through the group and this seems to have solved it..... in that this delay is now more or less constant.

    Cheers,
    Mal.

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    Re: Timing of shot pours

    Thanks Mal,

    I should have added that I always do a cleaning flush after making the coffee, and most Weekdays only use Silvia once in the afternoon.

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    Super Moderator Javaphile's Avatar
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    Re: Timing of shot pours

    Roughly 5 seconds from the time of turning on the pump until the first espresso shows is considered normal with a total extraction time of 30 seconds from turning on the pump until the shot is finished given as the standard. A good baseline to start from when experimenting with your machine/coffee.

    Java "Uuummm....That golden elixir..." phile

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    Re: Timing of shot pours

    Hi Bullitt,

    I also have a thermometer installed on top of my silvia boiler. To prime my machine I run brew switch until the boiler light comes back on.

    I was wondering at what point (temperature and time after light comes on) during the boiler re-heat phase do you pull you shot? When boiler cycle is done, the light switches off at around 105C and continues to rise to 110C. I think the low temps is because the silvia lives outside in the cold.

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    Re: Timing of shot pours

    Quote Originally Posted by Wushoes link=1148354334/0#4 date=1148363501
    the light switches off at around 105C and continues to rise to 110C. I think the low temps is because the silvia lives outside in the cold.
    isnt anything over 100 to high?...i was always lead to believe that optimum boiler temperature was around the 92 to 98 range, and that anything over 100 burns the beans.


    DD

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    Re: Timing of shot pours

    Ill second DDs comment. Personally, I think pulling a shot straight after the boiler light goes out would be too hot. Try flushing the group head when the light goes out (be careful) youll see that there is steam and boiling water. At the other end of the scale when the light goes on its too cold. Dare I refer back to the nude PF. It very easy to see the difference in the crema. So after making sure your boiler is full, Id be tempted to wait a nominal period after the light goes on or off to keep the shots consistent.

    Boris.

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    Re: Timing of shot pours

    With Silvia pre-heated I get very good results pulling shots around 2.5 minutes after the boiler light has turned off. I think they call this reverse temp-surfing?

    Ive been meaning to play around with timing shots "forward" from the time the boiler light turns on; this would be more convenient (not needing to wait for the cool-down).

    - Rob

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    Re: Timing of shot pours

    Quote Originally Posted by Derkdigler link=1148354334/0#5 date=1148367480
    Quote Originally Posted by Wushoes link=1148354334/0#4 date=1148363501
    the light switches off at around 105C and continues to rise to 110C. I think the low temps is because the silvia lives outside in the cold.
    isnt anything over 100 to high?...i was always lead to believe that optimum boiler temperature was around the 92 to 98 range, and that anything over 100 burns the beans.


    DD
    Two things need to be taken into account here; first, the water will lose heat to the group head, which is why its always good to have the machine on for the same amount of time before you temp surf, and to run the same amount of water through the group to start the temp surf. Second, the temperature at the top of the boiler is not the same as that at the bottom; ie. water doesnt heat homogenously ... sparkman and kaanage will be able to fill us in more about this.

    Anyhoo, the salient point is that absolute temperature values are not worth bothering with. Temperature measurement is usually only useful as a point of reference - let your tastebuds do the work.

    Just to keep it on topic, Im going to guess that the preifusion time issues are related to dose. Anyone care to test my theory?

    Cheers,

    Luca

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    Mal Dimal's Avatar
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    Re: Timing of shot pours

    Quote Originally Posted by Robster link=1148354334/0#7 date=1148388572
    With Silvia pre-heated I get very good results pulling shots around 2.5 minutes after the boiler light has turned off. I think they call this reverse temp-surfing?

    Ive been meaning to play around with timing shots "forward" from the time the boiler light turns on; this would be more convenient (not needing to wait for the cool-down).

    - Rob
    Thats what Ive read elsewhere too, I think from some of Sparkys experiment exploits..... waiting around 2.0-2.5 minutes after the light goes out seems to be the generally accepted ballpark for Silvias,

    Mal.

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    Re: Timing of shot pours

    I think that what Mark was saying was that after 2 to 2.5 minutes, the temperature gradient evens out more across the water that will be pumped through the puck, so that your intra-shot temp variation is the smallest possible ...

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    Re: Timing of shot pours

    Yep, when the element is in on/off mode (eg. driven by a thermostat) the on mode results in the hot element generating very hot water, which rises to the top of the boiler. This sets up strong convection currents driven by the heating of the water. During this time, the temperature can swing wildly as the hot and cold water are mixing. After the element has switched off, everything calms down. I saw the best temperature stability about 2 min after the element had switched off. The water temperature coming out of the group was about 92 C. During this test, my Silvia had been switched on for over 24 hours, so was well and truly heated.

    I wouldnt worry too much about the boiler wall temperature. Its going to be way hotter than the shot temperature. My PID is commonly set to 102 -103 C (measuring at the boiuler wall) for a 90.5 C shot temperature.

    Cheers,

    Mark.

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    Super Moderator scoota_gal's Avatar
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    Re: Timing of shot pours

    Quote Originally Posted by Wushoes link=1148354334/0#4 date=1148363501
    I think the low temps is because the silvia lives outside in the cold.
    :o aarrghh! The poor thing! This might be a bit personal and tell me if it is but why is your machine outside?? Are you not allowed to brew the good brew inside?

    And this has all been an interesting read for me, seeing as Im going to be a Silvia owner soon. Though I have one question...Does becoming an owner of a better machine make you want to be into such fine details to get the "god shot"? Or can I just continue on my merry way?? ;) Personally, at the moment I judge my shots by eye. (this is bound to get the fires of debate roaring I daresay. Exscuse me for doing so! But I am interested in what you all think!)

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    Re: Timing of shot pours

    Truthfully I think Id have no idea if I did get a god shot. I dont drink straight espresso so chances are that even with a macchiato Id loose the sublties of the perfect shot in the small dose of milk. I can say that 95% of my Silvia brews are bloody good (to me!) and I get good consistency from home roasting, fresh grinding and consistent tamp procedure. Sometimes my blends leave a lot to be desired, but hey thats half the fun with experimenting.

    The biggest varibale I have is frothing, some days are superb, others are ordinary - but no where near as bad as the cap I had this morning from the local cafe [smiley=thumbdown.gif] Way too much meringue and he kept topping it up with milk so that the meringue extruded itself in a nice souffle style cylinder about 2cm above the cup lip and sat there!

    In short if you are happy to continue on your merry way then you will be in hog heaven. But if you are searching for the holly grail then I guess a good machine will bring you a step closer - but who knows how far that god shot away it is!

    Matt

  15. #15
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    Re: Timing of shot pours

    ^Agreed, Matt. I am beginning to think that the "god shot" is the holy grail (I had a laugh) of coffee extraction and even then it is probably subject to personal opinion. My idea of such a shot being different to yours, that sort of thing.

    Not that I want to be seen as belittling the guys here for trying to reach that benchmark, I am just following their journey to it! :)


  16. #16
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    Re: Timing of shot pours

    My silvia lives outside coz i make a lot of mess while grinding and dosing....easier to just get the brush and brush all the lose grinds off the table and on to the ground :P

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    Re: Timing of shot pours

    Behmor Brazen - $249 - Free Freight
    Fellow CSs I am not sure how to post the link, but there is a good post on "Silvia temperature statistics" started by Robusto, currently a couple of pages back, which covers the whole boiler-grouphead temperature issue.

    In summary, measuring the top of the boiler with a thermoprobe will give a higher temperature than the water coming out the brewhead, typically by about 13 degrees C, so if you want to start your shot with the boiler top temp about 108-110 you will get water coming through the group head about 97-95 with a stability of about 1- 2 deg C temp loss during the pour.

    Then its a matter of fine tuning your grind and dosing.
    My original question was whether there might be something wrong with Silvia, or whether it is within normal times that users are seeing,
    BTW I am getting some great shots out of her,
    which echos another post somewhere that said best shots tend to be with updosing, fine grind and hot water



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