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Temperature of water without portafilter

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  • #16
    Here's a few hints to get the best from these machines. and work out what teh temps are actually doing.

    1) leave it on for at least 20 minutes before even thinking of making a cup. Have the PF locked in place and your cups, etc on teh warming tray.
    2) With a decent thermocouple, preheated under hot running water (not a meat thermometer) poke it up inside the portafilter and see what temps the PF is actually sitting at. you'd want it to be somewhere around 90'c
    If not, flush some water through and observe the temps.
    3) Next, observe the heating cycle and when the heating light turns off, purge some more water through and see what the temps are. this "should" be close to the highest water temp the machine will offer. Ideally 93-95'c is espresso temp
    4) If the "top of cycle" temp is too hot, then measure other points in the heating cycle to find your optimum temp.

    but ensuring both the PF and machine aswell as your cups are all warm before making a drink is vital to getting a cood cup

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    • #17
      Originally posted by TOK View Post
      Put your mind at rest, I'd say machine working as designed... That is a pretty realistic temperature reading, if all you have done is to flow water out of the group and stick a thermometer in the flow or in the bottom of a cup that is catching the group water.
      TOK is right, when I started out with a small single boiler I also thought I was experiencing the same thing. I got exactly around the same reading by just probing with a standard thermometer. It will never give you a true reading.

      Glad you got results with temp-surfing. That is also how I found out everything was just fine. Allow it to warm up 20-25mins to get somewhat of a more stable temperature as 'Robbks' suggested. I would not recommend relying on the cup warmer though, it won't do a good job. Just heat them with the hot water to make sure your shots drop into a 'friendly' temperature. It can make a difference. ;-)

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      • #18
        Anybody got a scace2 pf....?

        Maybe you could borrow him your Scace2...

        What machine do u use OP?

        If its compatible with the Scace 2.... i reccomend getting or buying one...

        I've been longing to get a scace 2 for perfecting my HX cooling flushes but never got one...

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        • #19
          A "Scase" is just a PF with a thermocouple attached to it.
          I built my own with an old unused single basket.

          drilled a small hole in the of the basket just off centre
          Attached the thermocouple securely with some conductive heatsink cement

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          • #20
            Hmm. I am not so sure about that Robbks.

            A Scace attempts to replicate the flow of a shot in addition to the thermal absorption properties of the coffee puck. The Scace II delivers temperature and pressure readings as well.

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            • #21
              The odd thing about that TC, is that surely you want to know what the temperature of the water is when it reaches the puck - not afterwards.

              Replicate the flowrate certainly (you could just use a needle valve), thermal properties seems less useful.

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              • #22
                Pics of Scace II showing internal anatomy and needle valve

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                • #23
                  Where is the needle valve? The brass fitting?

                  I wonder if, rather than trying to replicate the properties of the puck, the plastic insert is actually to minimise heat transfer between the water and the device, and to direct water onto the thermocouple at as close as possible to the inlet temperature.

                  May also improve the response time, by increasing the flow velocity over the thermocouple.

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                  • #24
                    Talk Coffee, Congratulations on getting a very expensive PF that championship baristas use......

                    How's your bank account?

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                    • #25
                      Flow rate and measured temperature are intrinsically linked in a thermofilter. The Scace uses not a needle valve per se, it's a fixed restrictor jet and a sintered bronze filter. The plastic insert is thermally inert so as to not absorb heat energy away from the brew water, which is losing heat very quickly when it exits the group. Thus if you have a ristretto flow rate, your brew water is cooling in the puck or thermofilter and resulting temps read lower. Very easy to see if you can control the flow rate, as I do with my scace rip-offs for workshop use. I generally use flow rates quite a bit slower than the Scace gives. No numbers to quote, just an eyeball 'that looks like a shot I'd drink' flowrate.

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                      • #26
                        That is quite interesting. Makes you wonder what is really the variable of interest; temp into the puck or temp within it?

                        Does this observation differ between HX and double boiler machines at all?

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                        • #27
                          I think of it as a variable offset, so even on a supremely temp. stable machine, changes in flow rate will affect measured temps (Newton's law of cooling re. rate of change of brew water with respect to the temp of it's surroundings- once outside the group or group/boiler).

                          We know that water temp. inside saturated boilers (and mean temp inside HX tubes/group casting) is above our desired brew temperature, offsets of between a few degrees and 12 degrees are common. Thus desired extraction temp. as far as I am concerned is a function of internal water temp at source (maintaining temperature due to large thermal mass, and energy being put in) minus a variable offset dependent on how quickly energy is lost. If flow rate is higher, the water at source temp. is displacing the cooling volume in the basket/thermofilter more quickly.

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                          • #28
                            1+ to the coffee machinist...

                            Although not a HX, it does arguably make a lot of sense

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                            • #29
                              Originally posted by Dimal View Post
                              The machine maintenance guide on that site is very useful too....

                              Mal.
                              Re: Mal's qoute regarding the Gaggia Site ( maitenance) I thought I'd have a look over lunch - like ' do myself a favour' !

                              GAGGIA

                              So to all the pro's here - what gives ? An espresso machine repairer with Nail Polish !!

                              What's next in this crazy world ?
                              A mechanic with Eye Shadow n Lippy ?

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                              • #30
                                But doesn't the Scace2 also read pressure....

                                I think i would build a scace2 too, but where do we get the multimeter from.....

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