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Newbie q: should the PID temp drop rapidly during extraction?

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  • Newbie q: should the PID temp drop rapidly during extraction?

    Two part question really:
    1) Why does the boiler temp (according to the PID) drop rapidly during extraction? Shouldn't it stay more or less stable if the water's not being replaced with new colder water? Seems unlikely the extra air added would really drop the water temp so much.
    2) When I see eg the La Marzocco factory sets their commercial machines at 94 - would they stay at 94 through the pour? If my Lelit Combi starts at 96 it's at 88 by the end of a double ristretto. Is that perfectly normal?

  • #2
    Best to ask Charlie or one of the other good people at JetBlack Espresso, since they are the Aussie importers and distributors they will know what is considered 'normal' for one of these.
    What is most important though, is the temperature of the water landing on the coffee puck; you wouldn't want this wavering all over the place...

    Mal.

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    • #3
      Okay cheers; can owners of other units with PIDs say the temp doesn't change significantly during extraction?

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      • #4
        Originally posted by SpiralEscalator View Post
        If my Lelit Combi starts at 96 it's at 88 by the end of a double ristretto. Is that perfectly normal?
        Yes, on your machine this is normal. When you brew a shot, hot water is delivered from the top of the boiler as cold water is introduced at the bottom of the boiler by the pump.
        The boiler is quite small so the cold water coming in will drop the temperature in the boiler as you are seeing. The water being delivered to the group from the top of the boiler, however, should remain constant through the shot as the thermal mass of the complete group will help to stabilise any small changes.

        Other machines fitted with PID's are often heat exchanger systems or dual boilers. In a heat exchanger, the boiler is separate from the brewing path and the water remains constant in it during extraction so the displayed temperature wont change. In a dual boiler, the coffee boiler is much larger than in your machine so the change will not be seen.

        TLDR; it's working fine, no need to worry.



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        • #5
          Good one n'22...

          Mal.

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          • #6
            Much appreciated Noidle22, you really know this machine. You might be able to advise then: I’m pretty happy with consistency of dose/grind/extraction time but I've noticed the pressure gauge is often showing 13 bar. So I should probably be dosing less or grinding coarser, right?

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            • #7
              Originally posted by SpiralEscalator View Post
              Two part question really:
              1) Why does the boiler temp (according to the PID) drop rapidly during extraction? Shouldn't it stay more or less stable if the water's not being replaced with new colder water? Seems unlikely the extra air added would really drop the water temp so much.
              2) When I see eg the La Marzocco factory sets their commercial machines at 94 - would they stay at 94 through the pour? If my Lelit Combi starts at 96 it's at 88 by the end of a double ristretto. Is that perfectly normal?
              I have a Lelit Victoria and PID temp doesn’t change at all during use. Is ready to go at the same temp following shot.

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