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  • A BM or a HG problemo ?


    The problem Im having is when I do a roast over 300 grams in the BM nowadays Im getting a small percentage of beans, normally around 20 grams worth, which are not roasting past a beige colour (not to FC).

    I roasted 300 grams of the Red Sea Blend a few weeks back and it looked good, except when dumped into the cooler a small pile of unroasted (not green) beans landed on top with chaff.

    I just did a 560 gram (6 bean blend) roast and exactly the same thing happened. I picked out 20 grams worth of unroasted beans. During this roast however I could see a yellow coloured bean or two do a lap of the BM bowl every now and then. So it was in the direct firing line of the HG yet didnt roast property.

    I have done a few smaller roasts, ie 200 grams worth, with no problems.

    Cant figure out if its the HG or the BM, however both seem to be working well :-/

    Could it be the beans themselves?

    Belinda, the Perplexed

  • #2
    Re: A BM or a HG problemo ?

    Belinda,  

    it could be that the paddle is slipping upwards on the agitator-pin and not skimming the bottom of the bin...

    i had that happen to my "roasting" bin (which has an aftermarket paddle in it..) and had to resort to pushing down on the centre of the pin/paddle-sleeve with a wooden spoon handle for the first few minutes of a roast, until the metal of the pin/paddle had heated enough to expand and keep the paddle securely on the pin.


    hmmm, lot of pins-and-paddles there...
    cheers,
    L

    Comment


    • #3
      Re: A BM or a HG problemo ?

      Hi Perplexed.... ehhh.. should I say Belinda...

      Been a while since we have had a Corretto thread.

      Well my observations (for what they are worth)..... having done more Corretto roasts than I can count. :

      Pre roast blends can give you uneven roasts..... normally they look uneven but all would be somewhere between FC and SC (assuming you stop just into SC).

      For these (and some other SO beans which vary a lot in size) I slow the roast down.... aiming to pull it at about 18-20 minutes for SC (FC around 10 minutes).... and find the longer roast between FC and SC evens things up a lot.

      But there is also a "design" issue with the Corretto (well hey it is a bread machine after all) with larger roasts (well above the paddle) where beans at the base get lazy and want to stay there (often the smaller beans).... and they just go round and round on the bottom- so dont get roasted as much.

      Also are there circular score marks around the bottom of the bowl beneath the paddle?..... I found that beans get wedged under the paddle - pushing it up and remain jammed underneath as it rotates.... these dont get roasted and push other beans around which also stay on the bottom (makes the problem above even worse).... small beans even slip under the paddle whilst it is jacked up....

      So I modified my paddle even more (remember I cut the end off so beans wouldnt jamb between the end of the paddle and the side of the bowl). The centre of the paddle base holds it a bit above the base of the bowl..... so out with a file and modified the centre so that the paddle almost (i.e. less than 1mm) touches the base as it rotates.... The paddle is also fixed to the shaft with a bolt (tapped through the side of the paddle) which holds it firmly onto the shaft..... result - no beans underneath and no riding up during a roast.....

      The only time Im now getting slightly uneven roasting is when I emulate a popper and get to SC in 7 minutes or less.

      I doubt the HG is at fault.... they tend to either work or die

      Comment


      • #4
        Re: A BM or a HG problemo ?


        Thanks Lizzie and Java

        Yes, Ive battled the paddle rising problem with the beans getting caught underneath. Ive had a few beans get stuck underneath the paddle on occasions, but they are normally roasted nicely, if not too nicely. So I dont believe that is the cause of under roasting.

        It may be as Java suggests that with larger loads, ie above 300 grams that some of the beans are just rolling around the bottom of the pan for some reason.

        However Ive done large roasts previously and not had this problem.

        I did a Red Sea Blend, which has a good dose of small beans in it, a few months ago and it came out fine; brilliant in fact. That load was 260 grams though, which is close to my average roast.

        The 560 gram load I did today was 6 different beans, but all beans were about the same size ...............

        Belinda, the still Perplexed.


        Comment


        • #5
          Re: A BM or a HG problemo ?

          Originally posted by Corretto link=1179042112/0#3 date=1179044844

          The 560 gram load I did today was 6 different beans, but all beans were about the same size ...............

          Belinda, the still Perplexed.
          Belinda,

          What were the beans in that roast and how long were they roasted for?

          Yep, the beans which are actually stuck - and remain stuck - under the paddle can get over roasted - especially if some of the air from the HG hits the paddle.... but the ones which escape under are the ones which miss out. Ive also found I get better results if I keep the HG output away from the paddle.... so it blows just on the beans.

          Before my last "mod" to the paddle uneven roasting was definitely an issue with larger loads (I often do 500-600 grams)..... but not an issue any more (unless I do a super quick roast - this morning I did 300g of monsooned peaberry in about 7 minutes just for a taste comparison).

          Ive also started pre-heating the bowl to about 150C before introducing beans now the weather is a lot cooler.

          Comment


          • #6
            Re: A BM or a HG problemo ?

            Hi All,

            I think thats where my dual paddle Big Loaf works well, really agitates the beans very thoroughly and never seem to end up with odd beans that havent been roasted properly.... So, I guess it is possible that there might be a small "dead zone" in a single paddle BM. I guess in the overall scheme of things though, 20 grams of under-roasted beans out of a batch of up to 600 is not too bad really, probably more annoying than significant.

            Like JB though, I have tended to slow my roasts right down to similar times mentioned by JB above. The resulting completed roasts are very even and after resting for a few days, seem to have better flavour development too than previously shorter roast times, so maybe thats worth a try. All the best Belinda,

            Mal.

            Comment


            • #7
              Re: A BM or a HG problemo ?

              Thanks Mal.

              Yes, before I had this problem (which only started say 6 weeks ago) I could easily control my roast to take up to 20 minutes before pulling it.

              However now I cant seem to get it past 15 minutes, tops.

              So thats why Im also thinking that its my HG. Nothing has changed with the BM. The beans all whizz around nicely.

              Ive always had doubts about my dodgy GMC Platinum HG .............................

              I almost brought a digital Bosch yesterday, except Bunnings was out of stock :-?


              Belinda, the Perplexed one.

              Comment


              • #8
                Re: A BM or a HG problemo ?

                Gday Belinda,

                Have you tried measuring the air temp on top of the bean bed during a roast? Might be worth a go if the HG is starting to play up, at least you would know then one way or the other,

                Mal.

                Comment


                • #9
                  Re: A BM or a HG problemo ?

                  Originally posted by Mal link=1179042112/0#7 date=1179048594
                  Gday Belinda,

                  Have you tried measuring the air temp on top of the bean bed during a roast? Might be worth a go if the HG is starting to play up, at least you would know then one way or the other,

                  Mal.
                  Good idea Mal,

                  I set mine up at 250C at the surface of the bean mass..... and I find that gives great results

                  Belinda,

                  Maybe your HG fan is starting to fail...... less air being moved would give you higher temperature and a shorter roast time.

                  Comment


                  • #10
                    Re: A BM or a HG problemo ?


                    Originally posted by JavaB link=1179042112/0#8 date=1179048773
                    Belinda,
                    Maybe your HG fan is starting to fail...... less air being moved would give you higher temperature and a shorter roast time.

                    That could quite possible be it. It sounds normal, but Ive been struggling with roast times for the last few months.

                    Definitely got to get that new Bosch HG 8-)


                    Belinda, the not quite so Perplexed

                    Comment


                    • #11
                      Re: A BM or a HG problemo ?


                      Actually, now that I think about it, which I do, the lights on the GMC HG which are meant to show the temperature its at, are now only showing 300C max, which is about 1/2 strength.

                      They used to show 600C on full [smiley=vrolijk_26.gif]

                      Would that be the fan dying?


                      Belinda, the befuddled and slightly Perplexed, but not as perplexed as before.

                      Comment


                      • #12
                        Re: A BM or a HG problemo ?

                        Well it shows that something is certainly not right with the heatgun....

                        The temperature display should indicate the power to the element..... but they might also vary the fan speed ...... and the logic (solid state that is ) which does all this is in some strange state....

                        So yep, anything is possible.

                        Comment


                        • #13
                          Re: A BM or a HG problemo ?

                          Hi Corretto
                          The Bosch is a great heat gun.
                          I always do a 450gm batch in my BM (ultimate bakers oven II) and roasts take anywhere from about 16 - 18min depending i guess on outside temperatures etc. I dont bother runing heat sensors etc but i get a consistent roast every time and stop the roast either just on second crack or about 30sec into SC.

                          I start with the gun on 630 degrees and then anywhere from 15 - 30 seconds in FC i then dial the heat back down to 550 degrees so that the i get about 5 - 6 mins between FC & SC.

                          It will be interesting to hear how you go with a similar gun and how you control your heat settings.

                          Mal

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