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Thread: Large Home Roaster...

  1. #1
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    Large Home Roaster...

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    So... Im going to build a larger roaster. The bread maker isnt quite big enough (getting up to 1.1kg a roast though!)

    Am going to build something that will take about 2.5kg a run.

    I have access to some infrared bulbs (tubes) so am thinking something along those lines.. I also have a pocket electrician (licensed!!) and engineer so should be right on those front :D

    The question I have is:
    -What are the most important things that a roaster needs to do well?

    Based on my experience so far, I would list:
    constant and controllable temp
    even heat application (to beans / drum)
    chaff removal
    easy to fill / empty
    cool quickly (although i have a separate machine for this!)

    what else...!?

  2. #2
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    Re: Large Home Roaster...

    I think this is the calm before the storm of advice that will come you way.......hold on to ya hat, youll have tonnes of advice soon, this was a bit of a bump for the thread, it will be an intersting one!

  3. #3
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    Re: Large Home Roaster...

    thats what Im hoping for! ;)

  4. #4
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    Re: Large Home Roaster...

    What about consistent bean agitation?

  5. #5
    Senior Member Koffee_Kosmo's Avatar
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    Re: Large Home Roaster...

    These are decisions you will need to make early on in the planing stage

    Hi temp bearings or solid brass bearings
    Which ones will you use

    Direct drive or chain drive

    I may be wrong but unless your design has the infra-red bulbs shielded inside the drum you may not generate enough heat
    (Some roasters 100 + years old have shielded gas flame pipes in the centre of the drum)

    I think gas may be more suited than infra-red bulbs *for the size of roaster, so test before you build


    Industrial drive motor

    Carbon steel drum

    Large sight glass

    Variable speed drum

    Thats all for now
    If I think of something else I will post again

    KK

  6. #6
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    Re: Large Home Roaster...

    thanks :) Will discuss with my people in the know and come back with some answers and plenty more questions!!

  7. #7
    Mal Dimal's Avatar
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    Re: Large Home Roaster...

    Quote Originally Posted by 496D646467675D496D716F6D020 link=1250487046/4#4 date=1250510375
    I think gas may be more suited than infra-red bulbs *for the size of roaster, so test before you build
    Agreed,

    Also much more efficient if executed properly and considerably cheaper to run for an equivalent thermal output.

    Should also consider an integral air blower to circulate heated air through the beans as they are lifted and dropped by the drums internal lifter bars. This will ensure that you are not solely relying on thermal conduction or radiation from the drum and beans (depending on heating system and its location).

    Depending on where you are going to site the Roaster, you may have to give some thought to the inclusion of an exhaust scrubber of some description, lest you incur the wrath of nearby neighbours or local authorities. Dennis of Cuppacoffee may be able to give you some advice in this area as I believe he has come up with an innovative solution.

    A Destoner? Some simple and relatively inexpensive designs around....

    If youre likely to stick with Electrical Heating, you should also consider going with a 3-Phase Power Supply to reduce line currents and also the use of 3-Phase Motors (in standard frame sizes).... Much more efficient and considerably simpler (and cheaper) than 1-Phase equivalent rated motors.

    What form of control are you going to implement, to manage roast profiles and logic control? A small PLC with included PID capability would be very economical and depending on the User Interface (Basic versus Convenient and Sophisticated) could be made very simple to operate. Manual Control Override which ever system is used in the event Power Loss occurs so that the Drum can be emptied... May catch fire if power loss occurs towards the end of a roast.

    A Failsafe Emergency Shutdown system to prevent catastrophic outcomes. Fire extinguisher....

    A Bean Trier to monitor batch progress...

    Insulation between Drum & Fire Sections and all external surfaces. Materials such as Fire Bricks and/or Lined Ceramic Fibre Wool, or Ceramic Mortar that is then lined (to prevent stray fibres migrating to where theyre not wanted).

    Basic Instrumentation such as a Bean Mass Thermometer, Exhaust Temperature and maybe Drum Air Temperature...

    Thats a few things off the top of my head anyway.... :)

    Mal.

  8. #8
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    Re: Large Home Roaster...

    Hey Menace!

    As mentioned today, Ive found a suitable drum - about 10litres capacity.
    Will look at getting 250W Halogens and their ceramic tombstones (springy holder doovies), and mount 2/3 of the way around the drum.

    If we leave one side of the drum clear of elements/globes, a chaff chute could be fashioned to remove the flammable material.

    (Im envisaging mounting the entire drum, with cage and globes on about a 30degree angle, with agitators inside the cage (ala cement mixer)

    Jst gotta find some stainless mesh to build the cage, with perforations big enough for chaff, and small enough to prevent beans escaping...

    NW

  9. #9
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    Re: Large Home Roaster...

    Behmor Coffee Roaster
    Make sure you drop in occasional pics. Looking forward to seeing the developments.



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