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  • New coretto setup - questions

    Hi all, I’ve recently been playing around with my first coretto setup. Sunbeam Quantam Smart Bake BM7800 bread machine and a Bosch 2 speed heat gun. I’ve done 4 roasts in total, but only the last 2 with the DMM which I’m trying to manually log every minute and is loosely held in place by a clip, neither of which is ideal.

    Roast 1 - 300g Colombian (not CoffeeSnobs) – heard first crack, then got worried by smoke and pulled almost immediately – didn’t reach 2nd crack and wasn’t very nice. Perhaps CS6 or 7.
    Roast 2 - 300g Ethiopian (not CoffeeSnobs) – realised my mistake with Roast 1, but wasn’t paying enough attention and went somewhere CS11 - more like CS12 if there was one. Again, not very nice.

    I then got some beans and the DMM from beanbay.

    Roast 3 – 300g Colombian Volcan Galeras 15 July 2014 – generally went well, and although it was consistently above the profile (Sando’s excel based one) I aimed for, I found it stalled around 175 degrees for 3 minutes, so I then jammed the heat gun right in, and got first crack, but then quickly noticed the DMM said 220 so I dumped it. Profile below. I’ve been drinking this since the day after, and am generally pretty happy.
    Roast 4 – 300g Decaf WOW - 15 July 2014 - went ok, although it also seemed to stall around 175 for 2 minutes. Had quite a few problems with beans getting caught in corners, so they range from CS8, right up to past CS11. Profile below. Again, been drinking this since the day after roasting, and drinks ok, but not a patch on the brown version I’ve bought from Andy before.

    Problems I’ve found so far - the bread machine has a horizontal setup (wider than tall) which seems to be causing some beans to get stuck in the corners, plus the temp probe may not be reading right. The temp probe reading jumps around all over the place – dropping 3-5 degrees then rising the same in the course of a few seconds a fair bit. Not sure if this is due to the lack of depth of beans, or the dodgy clip is allowing the probe to get knocked around a bit. It’s the 100mm stainless probe. My logging also needs some work - particularly following 1st crack

    I plan on trying a bigger roast, say 400g to see if I can get better stirring, or perhaps just extending the paddle. I’ll also set the laptop up once I have the probe issue sorted.

    I’d like advice on a few things if possible:
    How close do people have their heat gun nozzle to the beans, and do you physically vary this much within a roast? I find even though I have a stand, I keep trying to adjust it mid roast as it isn’t near the preferred profile.
    Do you think it is worth trying a bigger roast or extend the paddle, or should I just look out for a deeper, less wide BM which will hopefully solve the lack of agitation and the probe issues. I’d ideally like to be roasting around 300g due to lowish consumption levels.
    Also, the crema on roast 3 and 4 is great immediately (75% crema), but drops out and looks watery within a minute or two. Is this because they haven’t rested enough- they're only 3 days old.

    Thanks in advance!
    John
    Attached Files

  • #2
    Depending on the vacinity of the heat gun to the probe you can skew the reading, example you said you jammed the gun in, by doing so the heat source also gets closer to the probe (and maybe in this case you had put it directly at the probe). prior to making a cover for my corretto setup I had to vary distance and power during a roast. I never dip the nozzle right into the bread maker rather just above or just under the top edge, without measuring I'd say a good 10cm away from from the surface of the beans. You don't want to scorch the beans.

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    • #3
      Well done, it sound like you're on the right track!

      I don't use a DMM for mine but I previously drilled a hole through the breadmaker and pan to insert one. Keeping it near the bottom of the beans, in a consistent location would be essential for any batch to batch comparison. I have one of the smaller square tin breadmakers and do 400g batches, I'm not sure how suitable bigger breadmakers are for <400g.

      Also, I used to vary the height of the HG over time (attached to a beer capper). I worked out though, that I could keep my heatgun at the top of the pan on the lower setting (350C from memory), and cover the pan. To cover I just fold some alfoil and wrap it over the top, works a treat. I've been getting first crack 12-14 mins, second crack ~5-6 mins after without any variation in heat input. Near the end I slide some of the foil off to slow the heating and watch the beans reach 2nd crack.

      Comment


      • #4
        Hi J&C
        Welcome to home roasting! Sounds like you're well under way.
        I think that most rectangular style BM pans seem to start to sing at about 350g up, at least in terms of the mixing. This will also give a nice full coffee pouch
        With that batch size, the probe ideally should be about 10mm or so off the bottom, 2-3cm in, in the opposite side of the pan to the gun, always covered in beans. This should stop your measurements jumping. Mine is drilled through the back left corner…

        FWIW, if you're just starting off - don't try and 'surf a profile'. There is always a lot of temp lag with the guns and the readings - if you panic and try to speed up / slow down to follow the 'white rabbit' you'll always tend to over-compensate one way or the other.
        Burr's process would be a great one to get the ball rolling. Set your gun in one corner and near the top of the pan, cover most of the rest will alfoil. Leave the gun on one setting and measure the time to 1C. Then take off the foil to 2C to slow the roast down a little. Measure that time too. If it ends up around 17mins all up - perfect! Too fast? Raise the gun 2-3cm. Too slow - drop it a little. Taste every batch - then ask questions if you get funny tastes.

        Log all this on the DMM - just to remind you next time what happened this time. Remember - the profile is more of a reminder of what happened last time rather than what you should do this time (unless it was a perfect roast!) - it will be your notes of how you achieved any recorded profile that will shape the next roast (ie raised gun 3cm at first crack etc). I log all my gun settings now in the CS software - but before just used to write them on a paper sheet

        Enjoy the journey!
        Cheers Matt

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        • #5
          Thanks guys, some useful and simple tips. Think I was trying to get it perfect in one go with way too many variables.
          Will roast over the weekend and report back!
          John

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          • #6
            Bit of an update.
            Have played around and I've got the heat input side a bit more sorted. Heat gun now on lower heat but further in and pan partially covered.
            Still having trouble getting the beans evenly roasted with beans getting stuck in the corners unless I manually stir every now and then, so on the look out for a different bread machine.
            On the plus side, the batch I'm drinking now is actually pretty good to my taste buds

            Comment


            • #7
              Originally posted by johnandcass View Post
              Still having trouble getting the beans evenly roasted with beans getting stuck in the corners unless I manually stir every now and then, so on the look out for a different bread machine.
              Have you given some thought to modifying the stirring paddle(s) J&C?

              Some CSers have done this to alleviate the agitation issues you describe...

              Mal.

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              • #8
                Thanks Mal, but it appears the paddle can't be removed from the pan so was thinking a new machine might be simpler rather than coming up with a heat resistant food grade glue.

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                • #9
                  Originally posted by johnandcass View Post
                  a heat resistant food grade glue.
                  Whoa...

                  Don't know about using a glue - Was thinking more of a quick welding job, or maybe drill, tap and screw some kind of extension on to it. If the paddle can't be removed though, I guess that doesn't leave you with many options...

                  Mal.

                  Comment


                  • #10
                    Sometimes a paddle can be removed by removing a circlip under the pan and pulling the whole thing up through the bush/bearing?
                    I tested a paddle extension on mine by folding some sheet metal up and just wrapping it around the paddle in various spots… When I got it right - I pop riveted it

                    Comment


                    • #11
                      Originally posted by Dimal View Post
                      Whoa...

                      Don't know about using a glue - Was thinking more of a quick welding job, or maybe drill, tap and screw some kind of extension on to it. If the paddle can't be removed though, I guess that doesn't leave you with many options...

                      Mal.
                      Originally posted by DesigningByCoffee View Post
                      Sometimes a paddle can be removed by removing a circlip under the pan and pulling the whole thing up through the bush/bearing?
                      I tested a paddle extension on mine by folding some sheet metal up and just wrapping it around the paddle in various spots… When I got it right - I pop riveted it
                      Unfortunately no circlip and the shape of the pan means I can't screw or rivet something on. Will check with a mate who might have a welder, but in the meantime will keep an eye out for another second hand bread machine. Thanks for the tips though.
                      Regardless, loving my most recent batches

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