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Thread: Newbies thrifty vacuum bean cooler by a newbie

  1. #1
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    Newbies thrifty vacuum bean cooler by a newbie

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hot Bean Cooler Mark 1 (for an 85g. batch of hot beans ex corn popper)
    Materials:
    - 2 litre or larger bottle (ex fruit juice, emptied, rinsed and dried).
    - Steel can (ex sliced peaches, emptied, rinsed and dried).
    - Square of metal fly wire (sides longer than diameter of steel can).
    - Cable ties (enough to join together to go around circumference of steel can).
    - Good will (sufficient to borrow a pencil, pair of scissors, can opener and vacuum cleaner).
    Manufacturing the plenum:
    Using the steel can trace a circle, on the label of the juice bottle with the pencil,
    cut along the pencil line with the scissors and remove the circle.
    Before returning the scissors make a series of cuts into the wall of the bottle 5 to 10 mm. long perpendicular to the circumference of the circle.
    Manufacturing the sieve:
    Cleanly remove top and bottom from steel can using the can opener.
    Cover the open bottom of the can with the wire mesh and use the cable ties to attach firmly.
    Assembly:
    Insert sieve into circular hole in plenum.
    Insert vacuum cleaner pickup tube into mouth of plenum chamber.

    Iím sure the use of this equipment wonít need further description ( after the roast has cooled the vacuum cleaner is useful for a cleanup).
    My very first roast 6th Mar 09 the above described device worked perfectly for me, cooling was very efficient.


    Hot Bean Cooler Mark 2 for a Corretto size batch of beans
    (and my first Corretto roast 22th Mar 09)
    Materials:
    - 4 litre or larger plastic pail with press on lid
    - Steel can (say twice or more the volume of the roast beans to be cooled)
    - Square of metal fly wire mesh (sides longer than diameter of the steel can)
    - Cable ties or metal hose clamp(long enough to firmly attach wire mesh to can)
    Manufacture:
    Using the steel can as a template trace a circle on the lid of the pail and cut out the circle.
    Using the vacuum cleaner tube as a template trace a circle on the side of the pail and cut a hole to suit.
    Cleanly remove top and bottom from steel can.
    Cover the open bottom of the steel can with the wire mesh and use the cable ties or hose clamp to attach firmly.
    Assembly:
    Fit the lid to the pail and insert the sieve into the circular hole in the lid of the pail.
    Insert the vacuum cleaner hose into the hole cut in the side of the pail.







  2. #2
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    Re: Newbies thrifty vacuum bean cooler by a newbie

    Ingenious!

    How quickly does it cool and for what sized batch(es)? Our current cooler is about 2mins for 500g roasted beans (down to just above room temp) - not bad, but wed like to be able to cool a kilo or so at least that quickly.

    Also, how does the vacuum cleaner handle it? Would it be wise to, say, remove the bag so that the hot air can more easily be passed through the v/c? We have an old v/c that might do the job, but with our intended future batch size to be 1kg+, I wouldnt want to burn it out...

    Cheers
    Stuart.

  3. #3
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    Re: Newbies thrifty vacuum bean cooler by a newbie

    I was surprised just how quickly the beans cooled down but did not time the process.
    I havent done extensive work on this project just two different size steel cans first a 450g. then a larger one that was just half filled by my hot beans (originally 250ml. of PNG Wahgi) that was the limit of the two litre juice bottle which is too small for an 850g. can.
    Currently I have my eye on a large Milo can that the kids are still working on.
    My impression is that any mains voltage vacuum cleaner will move more than enough air to approach optimum cooling on Corretto size batches, what the limits are is too big of a question for this newbie with only 5 roasts under his belt.
    My old Electrolux seamed to take the task in its stride, I left the bag in place and it collected a little chaff I guess.
    The wire mesh offers very little resistance.
    Resistance would be offered by cross sectional area of the bean mass and the depth of the beans.
    My instincts tell me for the most effective cooling that taller is better than squat.
    But like I say "what the limits are is too big of a question for this newbie with only 5 roasts under his belt".

  4. #4
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    Re: Newbies thrifty vacuum bean cooler by a newbie

    Stuart Ive been using my old shop vac for over two years without a problem.
    A plastic bodied normal vac might be a different story though.

    Recently I took the motor out of one of those and built it into a cooling bucket - so far so good.
    It only needs to run for about a minute to cool down a 500g batch.

    Quote Originally Posted by 6461666C7B69717A69080 link=1238024012/2#2 date=1238034619
    My instincts tell me for the most effective cooling that taller is better than squat.
    I disagree.
    From my experience you want more surface area exposed.
    If the beans are in a taller profile they tend to bunch together and restrict the airflow.

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    Re: Newbies thrifty vacuum bean cooler by a newbie

    Quote Originally Posted by 023E2338323324313932560 link=1238024012/3#3 date=1238042960
    I disagree.
    From my experience you want more surface area exposed.
    If the beans are in a taller profile they tend to bunch together and restrict the airflow.
    I found the same.

    Had a colander in the top a bucket first. This cooled 300g in about 3 minutes when hooked up to a 1600W vac.
    I tried using a fan from a server tower (120W fan). I thought that a vac is high presure, low flow. A fan low pressure, high flow. This didnt work. Took forever to cool down.
    Also found that colander acted as a heat sink. It was more like vac was cooling down the colander which then cooled the beans.

    I then got one of those gold panning/geology sieves. Using the fan, not the vac, cools my beans down in about a minute. Room temp in about two. Probably cool even faster with the vac.

  6. #6
    Senior Member redzone121's Avatar
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    Re: Newbies thrifty vacuum bean cooler by a newbie

    I dump 750gms (up to 1kg) on to a mild steel plate 1m x 1m and about 8mm thick and blow a pedestal fan over them. 2 minutes tops to room temp. Single layer with space between them and a cold slab to dump them on. Even in our summer 30deg the steel remains cool.

    Whatever works for you ;)

    Chris

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    Re: Newbies thrifty vacuum bean cooler by a newbie

    30 degree summer? thats a nice autumn day...

    I dare say that steel might heat up on one of those 47 degree days we had a couple of months back. still, that sounds good for the rest of the year. You could always use a slab of copper with cooling fins (as per CPU coolers) if you wanted to go overboard!

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    Re: Newbies thrifty vacuum bean cooler by a newbie

    Stuart asks: "How quickly does it cool and for what sized batch(es)? Our current cooler is about 2mins for 500g roasted beans (down to just above room temp) - not bad, but wed like to be able to cool a kilo or so at least that quickly."
    I wonder what area a kilo of beans would cover as a monolayer?
    This evening I tried to measure rate of cooling using Mark 2.
    After 1 minute I jammed my finger into the bean mass and found the temp was close to ambient temp, the thermocouple probe was still indicating an elevated temp. Explanation: the apparent rate of heat loss from the probe is slow compared to the cooling of the bean surface.
    To answer Stuarts question perhaps a controlled experiment using a non contact thermometer or simultaneous multiple bead thermocouples monitoring different depths in the bean mass would be helpful (I dont have either).
    In my mind, for convenient effective air cooling the important requirement is to ensure adequate air flow over all beans. The perfect solution may require a mono-layer and apropriate air flow but for me and the batch sizes I currently use the described equipment (Mark 1+2) seems satisfactory.
    1).A vacuum cleaner really moves a lot of air and is available: for me one problem solved.
    2).Retaining the beans and subjecting them to a adequate share of the airs cooling effect: my compromise leans in the favour of conveinience of scale and ensuring best use of the available air flow(see diagram).



  9. #9
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    Re: Newbies thrifty vacuum bean cooler by a newbie

    How did you know what our cooler looked like?! ;) Our is the third pic in your diagram (except with an extractor fan). FWIW, we stir the beans briskly for exactly the reason your diagram illustrates. Not ideal but ok.

    Cheers
    Stuart.

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    Re: Newbies thrifty vacuum bean cooler by a newbie

    Cooling data reorded using the thrifty vacuum bean cooler.
    On the 8th of April I got hold of a more responsive thermometer and measured cooling after two roasts (Ethiopian Gambella and PNG Wahgi AA from just before second crack began).

    Bean Mass: *height = 112.5mm. *diameter = 84mm
    Thermometer probe inserted from top 85mm down into the bean mass
    The mark 2 air plenum was employed (see original post).
    Air movement: suction was provided by my trusty unmodified Electrolux 725 through a stock cloth bag (removed the PID for the purposes of this test).

    Cooling event 1
    (Ethiopian Gambella, 300 grams @ about 215 degrees C)
    Ambient temperature was 17.0 degrees C
    Atmospheric pressure 1024 millibars
    Temp after 1.5 minutes cooling = 25 degrees C
    Temp after 2.0 minutes cooling = 17.4 degrees C (plateau reached)

    Cooling event 2
    (PNG Wahgi AA, 300 grams @ about 215 degrees C)
    Ambient temperature was 16.7 degrees C
    Atmospheric pressure 1024 millibars
    Temp after 1.5 minutes cooling = 25 degrees C
    Temp after 2.0 minutes cooling = 17.0 degrees C (plateau reached)

  11. #11
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    Re: Newbies thrifty vacuum bean cooler by a newbie

    Behmor Coffee Roaster
    I found a second hose for the vacuum cleaner (Electrolux 725) and connected it to the air outlet (now have vacuum and blowing available) very useful during the roast.
    Use the blowing hose to:
    - blow away the chaff from inside the Corretto etc. earlier in the roast
    - cool anything that needs it (beans, heat gun....)
    Then use the vaccum hose and apparatus above to cool the roast as described.
    Lindsay



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