Announcement

Collapse
No announcement yet.

IR Roasting Possibilities

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • IR Roasting Possibilities


    Id like to get the ball rolling for discussion on what I believe could be the next generation of heat generation for roasting our beloved green beans to their ultimate state of roasted perfection.

    Naturally Im looking at it from the perspective of replacing the HeatGun for the Corretto aka Breadmaker style of roasting.

    From days of Googling, looking at hundreds of pages of ceramic elements, lamps, radiators, spot heaters and all manner of things Im yet to find the ideal solution for roasting. I know its out there, but hopefully CSers can find the ideal solution to suit us at a good price.

    In theory this should work. I saw a IR bulb/heat lamp on a German site, rated at 60 watts, that can heat the surface to near 300 C in a few minutes. But I cant seem to get back to that site for the life of me :-/

    Most of the Halogen/Quartz/Ceramic elements are rated up to 1500 watts however and can be used in rows.


    The main advantages of IR heating:

    * Heats the objects its pointed at without heating the air etc.

    * Its great at heating irregular shaped objects, ie coffee beans.

    * Small footprint, ie for directing into a Breadmaker or similar.

    * Very quite! no moving parts!


    It has been discussed last year on CS, but it didnt seem to go anywhere.

    http://coffeesnobs.com.au/YaBB.pl?num=1123478155


    Other great sites for info and inspiration are:

    http://www.heraeus-amba.com.au/infrared/index.php

    http://news.thomasnet.com/fullstory/28519/3167

    on the right track, but not quite right obviously http://www.rewci.com/hahewireauti.html

    http://www.infraredheaters.com/quartz.htm

    http://chinasuppliers.alibaba.com/search/china_products/Infrared_Heating_Lamp.html


    just for starters. many more sites on the subject and countless discussion papers.

    I know people will say it cant be done and it shouldnt be tried for this that and other reasons, but I believe this is the way of the future for the Corretto, and maybe drum roasting.

    It could open up other possibilities too that we havent even thought of yet




    Belinda


    Edited: AM 14-11-06




  • #2
    Re: IR Roasting Possibilities

    Belinda....

    Interesting idea- but the physics doesnt stack up.....(sorry )

    Lets assume ALL heat is transferred to the beans - none to the pan, the air or lost in any other way ( not practical however!)

    To heat 300 grams of beans to 220 deg C (assuming calorific value of beans is similar to water) is 66,000 calories

    That equates to about 264,000 joules.... or 74 watt hours...

    So if you want to roast in 15 minutes that will then be 300 watts of heat required.....

    Now with the other losses- and the efficiency of the heat source etc..... that may be even doubled.... could be as high as 600watts.

    OK thats a lot better than the heatgun... but you are talking a serious IR source.....

    And the above is "Best case" and doesnt take radiation from the beans, the corretto bowl (a great heatsink), convection of air currents generated from heating the beans and the endothermic reaction at first crack (which absorbs heat).....

    Yes, it is possible, Yes it might be more efficient but I dont think it would be significantly so...

    The saving is really no moving parts!

    Sorry for such a technical spiel..... boy I need a coffee now ;D

    EDIT: and I forgot you normally try to get the beans up to near first carck fairly quickly (say in half the roasting time) - that would require almost double the heat O/P from the IR source. We are now near the 1200 watt mark!!!

    Heat guns are relatively efficient - just not reliable.

    And by the way, the HotTop already uses this technology.... a heating element which just glows red has almost all of its energy in the IR spectrum - an electric element is also almost 100% efficient at converting electricity into IR (a little energy is in the long wavelength visable spectrum- hence the red glow).

    Comment


    • #3
      Re: IR Roasting Possibilities

      Parabolic solar heater for the greenest of green beans.

      Comment


      • #4
        Re: Solar Roasting Possibilities

        a heating element which just glows red has almost all of its energy in the IR spectrum
        ...like a heat gun element before you blow massive amounts of air across it?



        Parabolic solar
        Now your talking! I love the idea of using something like that but a very small focal area of energy prob means that you expel even more energy to move beans past that point.

        In the early 80s Tandy Electronics (Radio Shack in the USA) sold a Solar Cigarette Lighter that worked a treat (on a sunny day!) It looked like...



        The following page has some good starting data for building a "solar trough" (but I guess they really meant "solar roasting bed"






        images from: http://jc-solarhomes.com/fair/parabola20.htm

        Comment


        • #5
          Re: Solar Roasting Possibilities

          Originally posted by Andy Freeman link=1163388495/0#3 date=1163406807
          ...like a heat gun element before you blow massive amounts of air across it?



          Very true.... so efficient that without the airflow.... Scotty we have meltdown!

          Re the devices which produce very high temps very quickly - these are focussed IR sources where the energy is concentrated over a few square mm (small volume = large heat rise in a short time)- the ultimate being the laser! Your cigarette lighter is another example

          Unfortunately we need to heat a large volume fairly (very?) uniformly..... and not just the surface but the whole mass of the bean.... so most of these sources just wont work. (unless we also rotate the beans very quickly!!! - even then - the total energy required will still be high)

          Just looking at your trough boiler.... the tube could be replaced with clear quartz glass tube at the focal point and beans somehow forced through the tube at a controlled rate..... but I think the difference between first crack and charcoal might be a little hard to control ;D

          Comment


          • #6
            Re: IR Roasting Possibilities

            http://www.solarroast.com/about.html


            Java "Anything is possible when you put your mind to it!" phile
            Toys! I must have new toys!!!

            Comment


            • #7
              Re: IR Roasting Possibilities

              Originally posted by Javaphile link=1163388495/0#5 date=1163409107
              http://www.solarroast.com/about.html


              Java "Anything is possible when you put your mind to it!" phile
              No it isnt......

              There is NO way I could convince my wife to allow me to have something like that in the back yard!

              Comment


              • #8
                Re: IR Roasting Possibilities

                Originally posted by JavaB link=1163388495/0#6 date=1163410135
                Originally posted by Javaphile link=1163388495/0#5 date=1163409107
                http://www.solarroast.com/about.html


                Java "Anything is possible when you put your mind to it!" phile
                No it isnt......

                There is NO way I could convince my wife to allow me to have something like that in the back yard!
                Not even if you could show that it could bring in enough extra cash to pay all the bills with? ;D ;D ;D


                Java "Definate possibilities!" phile
                Toys! I must have new toys!!!

                Comment


                • #9
                  Re: IR Roasting Possibilities

                  Originally posted by JavaB link=1163388495/0#1 date=1163391650
                  EDIT: and I forgot you normally try to get the beans up to near first carck fairly quickly (say in half the roasting time) - that would require almost double the heat O/P from the IR source. We are now near the 1200 watt mark!!!
                  Java Java Java. You just make me want to prove you wrong now ;D

                  I was anticipating this response.

                  The point is that IR heat, halogen if you will, heats the objects theyre aimed at.

                  BTW the elements Ive looked at are all 1500 Watt plus, per element.


                  Belinda

                  Comment


                  • #10
                    Re: IR Roasting Possibilities

                    Originally posted by Corretto link=1163388495/0#8 date=1163429315

                    Java Java Java. You just make me want to prove you wrong now ;D

                    I was anticipating this response.

                    The point is that IR heat, halogen if you will, heats the objects theyre aimed at.

                    BTW the elements Ive looked at are all 1500 Watt plus, per element.


                    Belinda
                    No problem Belinda....

                    1500 Watts would work.... It was the 60 watts heating to 300C which wouldnt :-/

                    The halogen "IR globes" are really just elements with reflectors behind them...

                    Ive still got a toaster which uses two bar type halogen "globes" and that works really well (Sunbeam Quartzline)..... but it is about the same power as the normal toasters with the wire elements- the big advantage is that if some kid (including big ones ) tries to remove a stuck piece of toast with a metal knife - they wont get electrocuted.

                    For some reason this model was discontinued... and Ive never seen another since (from any manufacturer)..... but the idea was brilliant (maybe just too good)!

                    Comment


                    • #11
                      Re: IR Roasting Possibilities

                      Originally posted by JavaB link=1163388495/0#1 date=1163391650
                      EDIT: and I forgot you normally try to get the beans up to near first carck fairly quickly (say in half the roasting time) - that would require almost double the heat O/P from the IR source. We are now near the 1200 watt mark!!!
                      First carck?

                      I thought there was only one carck point.
                      Somewhere about Full French roast.

                      ----------

                      Andy, that Solar Lighter looks good, but at one bean at a atime it would take all day to do a roast.

                      Comment


                      • #12
                        Re: IR Roasting Possibilities

                        Originally posted by Thundergod link=1163388495/0#10 date=1163459079
                        First carck?

                        I thought there was only one carck point.
                        Somewhere about Full French roast.
                        HeHe.... You are correct ;D ;D

                        Bloody keyboards cant spell...

                        Well spotted

                        Comment


                        • #13
                          Re: IR Roasting Possibilities


                          Actually maybe the toaster method is sort of on the track there Java.

                          Im also thinking these ceramic elements could do the trick:

                          http://www.infraredheaters.com/ceramic.htm

                          an output of 700 C is close to a HG.


                          Belinda

                          Comment


                          • #14
                            Re: IR Roasting Possibilities

                            Originally posted by Corretto link=1163388495/0#12 date=1163462985
                            Actually maybe the toaster method is sort of on the track there Java.

                            Im also thinking these ceramic elements could do the trick:

                            http://www.infraredheaters.com/ceramic.htm

                            an output of 700 C is close to a HG.


                            Belinda
                            They look a lot better than the halogen.... halogen elements are normally in quartz glass and are easily damaged..... even by the acid in fingerprints.

                            The smoke from roasting and the chaff would probably coat the quartz and reduce the efficiency quite quickly. (The mirror backed globes have a normal glass outer but seem to only be available upto 350W or so.) The quartz ones would probably require a glass tube around them to protect them from the roasting process.... additional cost and difficulty.

                            No such worries with the ceramic ones!!! The only problem is they also seem to be fairly low wattage- upto 250W standard. - but might work OK---- might need to extend the time a bit.


                            I just checked the toaster elements - they are 900W.... a quartz tube inside of (I guess) a pyrox glass outer with a concave mirror behind to focus the heat onto the bread.

                            Comment


                            • #15
                              Re: IR Roasting Possibilities

                              Originally posted by JavaB link=1163388495/0#13 date=1163465659
                              The smoke from roasting and the chaff would probably coat the quartz and reduce the efficiency quite quickly. (The mirror backed globes have a normal glass outer but seem to only be available upto 350W or so.) The quartz ones would probably require a glass tube around them to protect them from the roasting process.... additional cost and difficulty.

                              No such worries with the ceramic ones!!! The only problem is they also seem to be fairly low wattage- upto 250W standard. - but might work OK---- might need to extend the time a bit.
                              Nothing the fan wouldnt fix :-)
                              and a bit of a clean now and then too.

                              I think it has possibilities.


                              Belinda

                              Comment

                              Working...
                              X