Results 1 to 6 of 6

Thread: Making the most of your popper

  1. #1
    Senior Member Dragunov21's Avatar
    Join Date
    Mar 2013
    Posts
    1,281

    Making the most of your popper

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi guys, I've been lurking for a while and figured that I might as well try and make my first post a good one. I know there's a fair few popper threads around the place, but a lot of them mention a limitation that can be fixed reasonably easily. Plus everyone likes pics, right?


    I started with a Target 900W popper and found that the limiting factor wasn't just the heating element, but also the fan. I was struggling to get it hot enough (<200) while maintaining a decent fluid bed (later realised that removing the outer casing dropped the temp substantially due to the fan pulling in cold air rather than pre-heated air passing across the heater housing).


    I grabbed a Homemaker (1150W) popper off gumtree and set to work on it with the goal of something that was pretty much set-and-forget, was hot enough to roast properly, could handle decent loads and was (most importantly) a piece of pie to put together with minimal materials/expertise.


    To cut a long story short, I assumed the heating element wouldn't be the limiting factor and decided to maximise airflow to allow the greatest quantity of beans to be loaded while roasting evenly then alter the air path if necessary to give the "best" chamber temperatures I could, easily. This amounted to enlarging the air-vents in the base of the chamber slightly then getting some exhaust-header sealant ($6 for a tube from SuperCheap Auto) and sealing the chamber to the heater housing (placing a full bottle of beer in the chamber to keep it weighted down). I then cut the "ceiling" out of the popper's external casing to encourage airflow past the hot chimney (made from coke-cans) and heater housing to keep temps up.










    115-130g loads provide chamber temps of 205-225C (increasing throughout the roast) that self-agitate by about ~30 seconds in (I use a wooden spoon during the first minute or so). For my beans, first crack starts at ~3:30 and second crack starts at 5:00-6:00, providing a roast that's even enough for my tastes (though I'd be interested to hear what people who actually know roasts think of them).

    The beans are CoffeeCompany's Bali "God Mountain" beans, which were easily my favourite out of the few varieties I got from them in a roasted sampler box. Stuff on the left goes in my french press, stuff on the right in my "espresso machine".

    Last edited by scoota_gal; 23rd March 2013 at 01:22 PM.

  2. #2
    Senior Member
    Join Date
    Oct 2011
    Posts
    1,376

    Re: Making the most of your popper

    Im no sparky, but in my two poppers, the metal sleeve in the roasting chamber is earthed. It could be just a compliance precaution or something, but It looks like they went to some effort in the designs to make it difficult to reach the metal components. Id be a bit worried about the electrically conductive chimney now sticking out the top if there is any risk of it being live...

    In my target popper, I max out at around 218C (bean mass temp); 225C would be handy.
    I tend to roast 90g batches, and dont have any problems with beans escaping (no chimney). I do three roasts in succession, and it fills a 250g bag nicely. Mind you, mine is automated, so I can turn it on and walk away for 15-20mins.

    And issues with tainting from the exhaust sealant?

  3. #3
    Senior Member Dragunov21's Avatar
    Join Date
    Mar 2013
    Posts
    1,281
    There is an earthing strap that would normally run from the heater housing to the metal sleeve (as you've said). I removed it, which was a personal choice based on professional knowledge of the potential risks. It's not necessary to perform the mod (you just have to cut a slit in the al. can chimney to allow it to slide around the earthing lug) and I do not recommend anyone removes theirs.

    If the metal roasting chamber remains earthed, so will any conductive sleeve you add to it.

    When you say bean mass temp, I assume you mean the temperature in the middle of the tumbling beans (as distinct from whatever the internal bean temp would be)?

    No issues from the sealant that I can taste, though I did run the popper for 10-15in before loading any beans to cure the sealant. I think there are RTV silicones that are available for temps up to 350C, which would be a better option if you were concerned about food safety.

  4. #4
    Senior Member
    Join Date
    May 2010
    Location
    Sydney North Shore
    Posts
    1,326
    Everyone should use the roasting methods that work for them.

    I use a non-modified Breville Bratz popper with a 415g salmon tin as a chimney which is an internal push fit with no glue needed.

    I get great results with about 180g of greens. I stir for a while with a wooden spoon handle until they spin unassisted and usually roast until just after second crack.

    Barry

  5. #5
    Senior Member Dragunov21's Avatar
    Join Date
    Mar 2013
    Posts
    1,281
    Nice; how much agitation are you getting once the beans are spinning? With the 900W I found that the beans would still move at higher loads but would roast unevenly (bean to bean, not so much across a single bean), presumably because the beans at the outside/inside of the mass were staying there.

    As I'm running it now I'm finding that everything's spinning pretty quickly with the whole mass becoming airborne every few seconds which seems to work well but I'm new to this and unsure how much is actually required (so, whether I can get higher loads and keeping the same temp by opening up the casing so cooler air is entering the intake).

  6. #6
    Senior Member
    Join Date
    Oct 2011
    Posts
    1,376

    Re: Making the most of your popper

    Behmor Coffee Roaster
    Quote Originally Posted by Dragunov21 View Post
    There is an earthing strap that would normally run from the heater housing to the metal sleeve (as you've said). I removed it, which was a personal choice based on professional knowledge of the potential risks. It's not necessary to perform the mod (you just have to cut a slit in the al. can chimney to allow it to slide around the earthing lug) and I do not recommend anyone removes theirs.

    If the metal roasting chamber remains earthed, so will any conductive sleeve you add to it.
    No worries. Not having the professional experience myself I probably err on the side of caution.

    Quote Originally Posted by Dragunov21 View Post
    When you say bean mass temp, I assume you mean the temperature in the middle of the tumbling beans (as distinct from whatever the internal bean temp would be)?

    No issues from the sealant that I can taste, though I did run the popper for 10-15in before loading any beans to cure the sealant. I think there are RTV silicones that are available for temps up to 350C, which would be a better option if you were concerned about food safety.
    Yep, measured with a bead type thermocouple moving with the bean mass. Thinking about adding another one before the roast chamber to reduce noise in the measurement.

    Another alternative to the can and sealant could be to use a silicone baking sheet. I've been thinking about using one as a funnel. Less sharp edges as a bonus!



Similar Threads

  1. making a tamper 1 on 1
    By Juanjo in forum General Coffee Related...
    Replies: 0
    Last Post: 7th March 2009, 09:41 AM
  2. Espresso making DVD
    By afton in forum General Coffee Related...
    Replies: 1
    Last Post: 15th July 2008, 08:19 AM
  3. making better coffee
    By talbashan in forum General Coffee Related...
    Replies: 13
    Last Post: 4th April 2006, 07:28 PM
  4. Making an impression - The Age
    By Andy in forum General News
    Replies: 4
    Last Post: 6th December 2005, 04:30 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •