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Copper roaster project

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  • Copper roaster project

    After being inspired by Gonzobs recent effort and as I am too tight to fork out for the "FZ-RR 700 Baby roaster", I decided to give a home roaster a go.
    This was my first foray into home roasting (this also is my first posting on CS) and have been very pleased with the initial results.
    The build was a lot of fun not to mention the roasting process itself
    Looking forward to some further experimentation...

  • #2
    Re: Copper roaster project

    Wow, that is an ace little roaster!

    Great job on the build, love the wooden handles - are there any vent holes at the end of the drum? Are you able to visually inspect mid roast?

    I just recently started using my baby roaster, these little copper drums are so much fun.


    • #3
      Re: Copper roaster project

      Thanks mate.
      One of the ends is silver soldered onto the shell and this has some 2mm holes for ventilation. The other end is able to be removed easily mid roast as it attaches to a threaded fitting secured to a central rod- about half a turn on the handle and its off.
      The Baby Roaster looks like an nice, well made unit- enjoy!


      • #4
        Re: Copper roaster project

        Hey, good effort! Quite a bit simpler than mine.

        Have another look at my one - I re-made the one of the handle mounts so I could get a thermometer through the handle. It makes a big difference to your ability to control the process.



        • #5
          Re: Copper roaster project

          See what you started Gonzo!

          Excellent work Silvermax, great to see another take on the home made copper drum roaster.

          I have some concern about the "hot spot" in the middle but your roast looks pretty even so it might be a non issue.

          (whacky thought of the day)
          I would really like to see someone try is to make one of these with a second outside layer of copper and then fill the air gap with between the inner and outer drum with hard packed salt or sand. In theory (well in my head anyway) it could produce a really steady inner temperature without any chance of hot spots and would be less likely to have problems with wind and ambient temperature fluctuations.

          Once again, great work and thanks for posting the thought provoking pics.


          • #6
            Re: Copper roaster project

            Wow, thats a fantastic looking roast you made with that fantastic looking roaster!

            How easily can you hear the cracks?
            Whats the wall thickness?
            Whered you get the pipe from? I asked Reece Plumbing but they wanted more money than the FZR1000 cost. Or was that an FZ-RR 700??? (old motorcycling joke)



            • #7
              Re: Copper roaster project

              Thanks Gonzo, Phil and Andy.
              To answer a few of the questions raised:
              The tube is 180mm long and although there does appear to be hot spot in the middle where the flame concentrates, I dont think this is a huge issue as the roasts are pretty even. The photos were taken after just a few roasts and there is now a much more even colour along the length of the tube after a further dozen or so. The tube is 16 gauge (1.6mm) and being copper, distributes the heat very well.
              I purchased the copper tube and ends from an Ebay seller ("gdayall"). Not sure if it was a once off sale or if he can supply more of the same. Cost was less than $50 delivered. The set was designed for model engineering (small boiler or tank fabrication) and was nicely finished. I did not price copper from Reece to compare.
              I like the idea of the thermometer in the handle. Unfortunately my design does not allow an easy retrofit as I have threaded rod down the centre of each handle- maybe I could have one penetrate the fixed end cap if needed.
              Im just starting with roasting at home so Im on a steep leaning curve, but I have been able to hear the first crack easily on all my roasts. Second crack is a bit more of a challenge depending on the beans, but I guess this will come with experience.


              • #8
                Re: Copper roaster project

                This kind of roaster looks really interesting. If anyone is after copper pipe then there is 5.2m of 100mm pipe on eBay at the moment (search "100mm B Grade Copper Pipe") that ends tonight and currently has no bids, although who knows what price it will go for. Its for pickup in Berwick VIC (Im in Sydney otherwise Id bid for it). 5.2m worth would make a lot of roasters!


                • #9
                  Re: Copper roaster project

                  Maybe I should grab this and divvy it up for interested parties. Hmmm an hour to decide...


                  • #10
                    Re: Copper roaster project

                    My Father-in-Law and I were also inspired by Gonzobs design, and decided to knock up one of these little copper drum roasters, too. (Sorry, no pics as yet). Weve only done three roasts with it, and were still fine tuning the set-up, but so far the results have been quite good - relatively even roast (surprising, actually, since we havent put in any kind of agitator yet... just giving it a good shake every couple of minutes or so), good flavour, crema etc. Having said this, there are two problems that Id appreciate a bit of help with:

                    Firstly, all the roasts so far have taken quite a long time - around 36 minutes, or so. Weve been using a little butane camp-stove, similar to Silvermax by the looks of it. We suspect we might have the roaster set a bit high off the flame, and were going to try bringing it down a bit. Are we on the right track here, or could there be something else going on that we havent thought of?

                    The second problem is that we havent yet been able to hear any cracks. At first we put this down to the copper pipe being too thick, but it looks to be a similar thickness to the material Gonzob and Silvermax have used (standard 80mm copper pipe from Reece Plumbing). You can easily hear the beans turning in the drum, so I would have thought the cracking would come through also. Is it possible that since the process is so drawn out that the beans are also expanding so gradually that they arent cracking audibly? Thankfully, we cut a large vent in the lid which conveniently allows us to take samples along the way, so its pretty easy to monitor the roast visually.

                    Bit by bit, were refining the design. If it still takes 30+ minutes after all of this, I reckon well be motorising it very soon! Any ideas how to do this?


                    • #11
                      Re: Copper roaster project

                      Originally posted by 65494649454946475D5B280 link=1326012396/9#9 date=1327579386
                      The second problem is that we havent yet been able to hear any cracks.

                      What beans are you using?

                      Peru Ceja De Selva is reknown for having loud cracks, so if you arent using that it would be worth giving it a try.

                      You could also try a few beans using a stainless steel bowl and a heat gun just to get a feel for what the cracks sound like, if you havent roasted before


                      • #12
                        Re: Copper roaster project

                        Thanks Trentski,

                        The last two batches have been using the El Salvador Finca Belvedere SHG from Beanbay. I did roast up a few batches with my old popper before it died late last year, but I cant recall how distinct the cracks were. Perhaps I should try a batch of other beans to see if they are any more distinct?


                        • #13
                          Re: Copper roaster project

                          Hi Manamanous.

                          Were waiting for those pics....!

                          I can easily hear the first crack with my copper roaster. I made a corretto-style one as well and I find it much more difficult to hear cracks on that because of the noise of the heat gun and the breadmaker drive. The copper is much more hands-on.

                          I think youre just not getting the copper unit hot enough. I have had roasts complete in less than 10 mins. On mine, the outside of the drum changes in colour as Im heating and turning it. You can SEE the colour change as you pass it over the flame. I have the tips of the flame touching the drum. The only roast I had that took more than 20 mins was one where the gas canister was almost out.

                          The problem I have with the unit is that the process can "run away" at the end. I get first crack, and in next to no-time its charcoal. I have to greatly reduce the flame, and even so I have only once heard second crack before its ready to empty out.

                          If you see my later mod where I put a thermometer up the axis of the handle, it makes it much easier to work out where you are. It needs to get to 210/220C inside the drum.

                          Remember to do the PICS!!!!



                          • #14
                            Re: Copper roaster project

                            Hmm- 36mins does sound like the roaster is simply not getting hot enough. All of my roasts have taken between 8 and 13 mins, depending on the type of beans. I usually pre-heat the unit for a few minutes beforehand also.

                            When I started off I had the flame at full for the full duration of the roast, but quickly learned that this was too aggressive. I now tend to have the flame at 3/4 strength and then lower to about a half at rolling first crack. This extends the total time to usually 10-13 minutes. I would agree that even then and without supervision the beans can darken up very quickly after first crack, but opening the end cap to inspect a few times after first crack probably helps in releasing some heat and to slow the process a bit.

                            I find also that picking up the roaster and tipping it from side to side a few times every minute or so helps to even the roast.

                            I hope you have some success after some tinkering


                            • #15
                              Re: Copper roaster project

                              Thanks for the feedback Gonzo and Silvermax.

                              It confirms what we were starting to suspect, that we had the roaster set too high above the flame and it simply wasnt getting hot enough. Were going to make some adjustments to the frame so that the roaster sits lower. Hopefully this helps. Will let you know how it goes... and yes, pictures too!

                              Cheers, M