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(Utility of) Installing a digital thermometer in a E61 group head

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  • (Utility of) Installing a digital thermometer in a E61 group head

    Hi everyone,

    I have seen around several photographs of E61 machines with a digital thermometer installed in the brew head by removing the nut that is right there.
    I am in doubt if to install this and would like your opinion. Is there anyone who has already done this and obtained a real benefit?

    Simpy put, my doubt is the following: why is that thermometer supposed to help?
    I mean, I know it offers a further indication of what's happening in the machine (and specifically the brew head, which will of course be lower in temperature from what the PID shows), but what's the point in knowing that the head is at 91.5 when the PID is at 94 if I already know that a certain type of coffee (for my taste) comes out well at 94?

    Is there any specific reason to install that?
    Cheers if you can read this or if you can enlighten me

  • #2
    I agree with you. I could see a use for it to monitor / test brew temp when tuning a machine (although a scace type device would be better). Once done then it is irrelevant for a normal machine and like you say for a PID DB if you know your offset the absolute figure is irrelevant.

    But some people love gadgets (I'm one) and like gizmos! I also think it doesn't do wonders for the look of the e61 machines having a digital thermometer sticking out in the breeze.

    Cheers

    Comment


    • #3
      For a dual boiler with PID I understand, but for a HX set to 0.8bar boiler pressure...what's the group head temperature?

      Comment


      • #4
        Originally posted by DavidJJ View Post
        Hi everyone,

        I have seen around several photographs of E61 machines with a digital thermometer installed in the brew head by removing the nut that is right there.
        I am in doubt if to install this and would like your opinion. Is there anyone who has already done this and obtained a real benefit?

        Simpy put, my doubt is the following: why is that thermometer supposed to help?
        I mean, I know it offers a further indication of what's happening in the machine (and specifically the brew head, which will of course be lower in temperature from what the PID shows), but what's the point in knowing that the head is at 91.5 when the PID is at 94 if I already know that a certain type of coffee (for my taste) comes out well at 94?

        Is there any specific reason to install that?
        Cheers if you can read this or if you can enlighten me
        On a DB machine with a PID I probably wouldn't bother either.
        On a Heat Exchanger machine it shows how quickly the group temperature recovers after you stop the pre-extraction flush. That gives you feedback, so you don't have to time the flush and time the recovery before you pull the shot in order to reproduce a certain temperature profile (the "hump" in the beginning).

        Comment


        • #5
          Thanks everyone for the informative replies. Yes, I was mainly referring to Dual Boiler Machines already fitted with PID.
          I understand the why on HX machines. I would like to hear a discussion between the "supporters/users" of these and the "an E61 machine doesn't need a PID" group of people.
          Cheers,
          David

          Comment


          • #6
            Originally posted by DavidJJ View Post
            Thanks everyone for the informative replies. Yes, I was mainly referring to Dual Boiler Machines already fitted with PID.
            I understand the why on HX machines. I would like to hear a discussion between the "supporters/users" of these and the "an E61 machine doesn't need a PID" group of people.
            Cheers,
            David
            I think the PID and the grouphead thermometer each serve a slightly different purpose, so one does not necessarily make the other obsolete. TBH This is not based on extensive hands-on experience, but merely on how I understand this systen is supposed to work. Sure, eventually the purpose is to control the brew temperature. However, the PID measures and controls the boiler temperature. The read-out may be either the real boiler temp or what the brew temp is expected to be at these boiler conditions. It is a point of reference, as is the pressurestat setting on a non-PIDed Heat Exchanger machine. However, the PID does not register the dynamics of how varying boiler conditions are passed to the grouphead, which is what the GH thermometer does.
            On a DB machine with an E61 head the water circulates between the brew boiler and the grouphead, so I would expect these dynamics are fairly straightforward. By flushing the group, one directs the grouphead temp up (with a lag) towards that of the brew boiler, which is controlled. On a HX machine with an E61 the temperature gradient between the boiler and the grouphead is a higher and more dynamic. By flushing, the steam pressure and thus the boiler temp drops, thereby starting a heating cycle and at the same time hot HX water is mixed with / displaced by fresh water, so it is less obvious where the group temp is going to end up. This is where the GH thermometer comes in and I feel its added value is not so much depending on whether the HX boiler is controlled by a PID or a pstat. The difference between a PID and a pstat on a HX machine is merely that with the PID the point of reference can be shifted more easily.

            Comment


            • #7
              After several years of using many types of machines, I am of the belief that that PID Controlled Brew Water Temp. coupled with an E-61 or other massive Group, is completely superfluous. The lag experienced between the time the Controller experiences a disturbance and when this correction is actually experienced at the Group Head is enormous. The only real-world benefit is the ease with which the PID Controller allows one to alter the Brew Water Boiler Setpoint, as pointed out above. The shear mass of the E-61 Group really renders the prospect of a useful integration of PID control, moot.

              If you're after truly effective PID Controlled output of the Brew water Temp., then you require a low-mass Group, an appropriate Input Power to Water Volume Ratio of the Brew Boiler and if coupled with a Group Head Heating Element, then very stable brew water temperature is possible.

              Of course, there are many ways of 'skinning a cat' in order to achieve an end-goal but PID Controllers coupled with E-61 Group machines is not the best way to go. Looks great of course but in a pure engineering sense, it doesn't make a lot of sense...

              Mal.

              Comment


              • #8
                Originally posted by Dimal View Post
                After several years of using many types of machines, I am of the belief that that PID Controlled Brew Water Temp. coupled with an E-61 or other massive Group, is completely superfluous. The lag experienced between the time the Controller experiences a disturbance and when this correction is actually experienced at the Group Head is enormous. The only real-world benefit is the ease with which the PID Controller allows one to alter the Brew Water Boiler Setpoint, as pointed out above. The shear mass of the E-61 Group really renders the prospect of a useful integration of PID control, moot.

                If you're after truly effective PID Controlled output of the Brew water Temp., then you require a low-mass Group, an appropriate Input Power to Water Volume Ratio of the Brew Boiler and if coupled with a Group Head Heating Element, then very stable brew water temperature is possible.

                Of course, there are many ways of 'skinning a cat' in order to achieve an end-goal but PID Controllers coupled with E-61 Group machines is not the best way to go. Looks great of course but in a pure engineering sense, it doesn't make a lot of sense...

                Mal.
                All depends on usage, I guess. I tend to have a couple of milk coffees in the morning, then if working from home, an espresso or long black in the early afternoon - giving plenty of time for the group to cool (I'll typically turn the machine off in between).

                Now, if I could control the PID and steam boiler off switch remotely via Google Home, it'd be even better [emoji848]

                Comment


                • #9
                  Originally posted by DavidJJ View Post
                  Hi everyone,

                  I have seen around several photographs of E61 machines with a digital thermometer installed in the brew head by removing the nut that is right there.
                  I am in doubt if to install this and would like your opinion. Is there anyone who has already done this and obtained a real benefit?

                  Simpy put, my doubt is the following: why is that thermometer supposed to help?
                  I mean, I know it offers a further indication of what's happening in the machine (and specifically the brew head, which will of course be lower in temperature from what the PID shows), but what's the point in knowing that the head is at 91.5 when the PID is at 94 if I already know that a certain type of coffee (for my taste) comes out well at 94?

                  Is there any specific reason to install that?
                  Cheers if you can read this or if you can enlighten me
                  I found the following link of someone who has actually installed such a device. Interesting, I tjhought.
                  E61 Grouphead Digital Thermometer Adaptor - Coffeetime
                  And of the installation of one.
                  https://www.chriscoffee.com/v/vspfil...ter_Manual.pdf
                  Too expensive for the value it adds, in my view.

                  Comment


                  • #10
                    As mentioned earlier in this thread, the heat retention characteristics of the E61 grouphead has an impact on brew water temp and this is something that isn't often explored.

                    An E61 grouphead thermometer can give some insights into how this plays out in real time. Once boiler temps are under control, the user introduces variables by the timing of heatup, flushes, recovery time between shots etc. These can all effect the E61 grouphead temp and can lead to brew water temp overshoot at times, I believe.

                    For non-PID E61 machines the grouphead thermometer can be a useful temp surfing tool. Also can be a bit of an eye-opener as to why a consistent and repeatable brew routine helps to get the very best out of the E61.

                    A couple of current threads on grouphead thermometers.

                    https://coffeesnobs.com.au/brewing-e...tml#post638348

                    https://coffeesnobs.com.au/brewing-e...tml#post639108
                    Last edited by CafeLotta; 17 October 2018, 08:59 PM.

                    Comment


                    • #11
                      Hi guys.
                      Bare in mind that i am a dual boiler user for years with all my sensors and prototypes used in it.
                      I have the PID model of Expobar and my experience plus other tenths of clients is pretty clear: there are differences between the PID and the final temp of the water that hits the coffee puck.
                      Some have adjusted the offset of the pid accordingly to the Coffee Sensor.
                      I have used the Universal Adapter and sensor and now, for two months, the pro version.
                      For example, my pid is setup at 88 degrees C, and my two or four extractions in the morning start at 90 degrees - 91. Without the sensor, what would have been the conclusion?
                      Very true and useful info are given and written here by Degaulle and Dimal. That's the hole truth.
                      Thanks.

                      Comment


                      • #12
                        Sometimes I wonder whether the grouphead thermometer is more useful than a pid as it lets one react to get the desired temp for brewing...

                        Comment


                        • #13
                          Originally posted by sxie View Post
                          Sometimes I wonder whether the grouphead thermometer is more useful than a pid as it lets one react to get the desired temp for brewing...
                          If you have a non-PID E61 grouphead machine it can be a very useful addition once you learn how to utilise the temp readings it gives you. If you have PID then I think a grouphead thermometer enhances the benefit of the more closely controlled boiler temps a PID gives you by providing an indication of brew water temps through the E61 grouphead. This is especially relevant to Hx machines I'd imagine. Flushing overheated brew water from a heat exchanger can temporarily overheat an E61 grouphead. Also can help with monitoring E61 heatup times and flushing effects on a PID Dual Boiler. Developing a reapeatable brewing routine and making adjustments based on what you're tasting in the cup also play an important part.

                          Personally, I'd love to see grouphead thermometers as standard equipment on E61 grouphead machines along with detailed instructions on their use. Probably won't ever happen as this would destroy the illusion that all E61 equipped machines, especially PID versions, provide perfectly accurate temp each time, every time. User input plays an important part in achieving a consistent result in the cup and a grouphead thermometer can help with this (in my opinion).
                          Last edited by CafeLotta; 12 March 2019, 11:25 AM.

                          Comment


                          • #14
                            I saw the screw hole on mine and thought about a thermometer. For now I have ditched the idea. Di Bartoli set the machine - HX with 2 litre boiler - up beautifully and I so a.cooling flush to sort out the dancing water and then pull the shot and to be honest I have never tasted better. I'm a convert. It's so repeatable just using the tried and true method. Same thing I did with my commercial with saturated groups but as good as it was this little (well...30kg) machine produces better shots and better microfoam.

                            Cheers

                            Comment


                            • #15
                              Originally posted by ozscott View Post
                              I saw the screw hole on mine and thought about a thermometer. For now I have ditched the idea. Di Bartoli set the machine - HX with 2 litre boiler - up beautifully and I so a.cooling flush to sort out the dancing water and then pull the shot and to be honest I have never tasted better. I'm a convert. It's so repeatable just using the tried and true method. Same thing I did with my commercial with saturated groups but as good as it was this little (well...30kg) machine produces better shots and better microfoam.

                              Cheers
                              Morning Ozscott, I've never felt the need to fit a thermometer to my machine, thought about it briefly early on in the piece, then thought why, what would I gain by knowing the temp? couldn't come up with a logical answer.

                              Your right re the ease of use, quality of coffee as well as repeatability of Bezzera machines, as per your comment, I doubt you could do better regardless of cost.

                              I know I must sound like a broken record, however the Galatea was an absolute pleasure to use from day one and it remains so to this day, the coffee it produces is nothing short of sensational, the rare failure I have is entirely due to operator error.

                              Comment

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