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Slowing down the roast

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  • #31
    Re: Slowing down the roast

    Sounds interesting lkaiseng. Can you tell us about your roasts. Any chance of some pictures?

    Cheers,

    Louis

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    • #32
      Re: Slowing down the roast

      Hi all, I was wondering how this would go in slowing the roasting process down.
      Splitting the popper into two circuits, fan and heater, as Mal has done, leaving the fan connected to the main on/off switch so that it is running whenever the unit is switched on, but having the heater on a separately installed switch so that it could be cycled on and off during the roast. The heater could be cycled say 1 or 2 seconds every 10, depeding on the profile of your popper.
      Its not exactly scientific, but it might help to gain a bit more control over the heating.
      All the best,
      Steve.

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      • #33
        Re: Slowing down the roast

        Hi louis, here my popper pics
        http://sg.pg.photos.yahoo.com/ph/ope...80.jpg&.src=ph

        My working bean mass is currently about 120g (going for more, so juz configured it for an untested higher fan voltage).
        For heat dimmer, at 30% setting, it gives me a slow ramp to 130 Celsuis in 6-7mins. From then on, 10% more pushes it pass 1C and 2C by the 8-9 min. (overlapping cracks, so trying different heat and fan settings for this stage). So about 5% of the beans are a bit too dark/oily spots.
        Cappuccino tasted fine this morning (after a day rest), truer test when i do an espresso later.

        Cheers!!

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        • #34
          Re: Slowing down the roast

          Hmmm,

          I would be a bit worried about the possibility of the two controllers getting slightly out of sync. For the Heating Element, you could build a simple Triac Output controller that could handle the full load on its own, very cheaply.

          Lovey,

          I havent really bothered with going any further than controlling the fan speed because for my needs, 100-120 gram batches are quite enough most of the time. Only time it would be handy to have more capacity is for when I roast batches as gifts for birthdays, Xmas, etc. Since I usually make these about 500 grams, 4-5 roasts per household at Xmas can wear a bit thin by the time I get about half-way through the list. But hey, Xmas is Xmas .

          How easy it is to split the Fan and Heater circuits depends a lot on the brand of popper you have. Some of them are remarkably easy to do and even have an A.C. Fan Motor which makes it even easier. The cheaper you go though, the more difficult it seems to become as the manufacturers try to cram as much as possible into the smallest possible space. You end up with both 240 Volts A.C. and 25 Volts D.C. on the same little Printed Circuit Board that is soldered to the Fan Motor connection tags. Makes it quite difficult to end up with an elegant solution for splitting up the supplies.

          Makes all of this very interesting to say the least. All the best,

          Mal.

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          • #35
            Re: Slowing down the roast

            Ok guys.
            We need some diagrams here ;D
            Cheers...
            Bruce...

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            • #36
              Re: Slowing down the roast

              My "cheap" solution to Variac is to use 2 dimmers set up in parallel.
              Since my popper is rated at 1200W, and the dimmer are 600W, putting them in parallel distributes the load.
              Very nice solution Kai Seng...
              and with the addition of a plug and a socket this could be used for many different projects.

              hmmm.......

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              • #37
                Re: Slowing down the roast

                Originally posted by Bruce link=1118894468/30#34 date=1120559452
                Ok guys.
                We need some diagrams here ;D
                Cheers...
                Bruce...
                Hi Bruce,

                Lots of info about this and much more can be found here... http://www.homeroaster.com/homemade.html.

                Cheers,
                Mal.

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                • #38
                  Re: Slowing down the roast

                  Hmm, my popper is taking less than 2 minutes 45 secs to first crack and 5 minutes to the second crack. If I go much longer than that, the beans end up very dark, oily and bitter.

                  And those roasts were done outside (for the cool air and to dispel the chaff) and on a couple of extension leads.

                  I may have to increase the air flow or reduce the heat. Ive got a Variac so Ill try that first.

                  Ron

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                  • #39
                    Re: Slowing down the roast

                    Those times equate to mine. Ive read much about using extensioin leads to increase the resistance and therefore get a lower voltage.... But I suspect thats usually the case in the US where electricity supply isnt as good as ours.

                    I constantly stir the beans with a long-handled wooden spoon so that they get a more even roast.

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