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First Timer - Coretto Roast w/ Temp Control

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  • First Timer - Coretto Roast w/ Temp Control

    Hi All,

    First of all, thanks to all the people on the forum for posting so much information. I managed to find all the answers I needed and was able to build the corretto without posting a question.

    As for the setup:
    BM: Panasonic SD-206: stripped, rewired with an On/Off switch and modified with a chaff chimney, temp probe, and shortened paddle
    HG: Bosch 630 DCE
    Bean Cooler: Metal Bucket, with exhuast fan
    DMM: Beanbay supplied and using RoastMonitor software

    I received the DMM and a CoffeeSnobs Beginner Pack, really happy with the products supplied, and the speed of the order.

    First Roast was the Ethiopian Gambella Sundried, roasted to 30 seconds past rolling first crack. Roast time was just on 12 mins.
    Still not sure about how it all went, but they came out brown and smelling like coffee so I can't be too far off the mark.

    Keen to hear your comments and experienced tips about it all.

    Side note:
    As a beginner, I'd like to make a suggestion that there be a sticky thread at the top of the home roasting section that lists in a level of order the different discussions that a beginner should read to gain an insight as to what they need to do. Whilst I managed to find all the information I needed using the search function, it took me about a week to cover all of the necessary topics. The problem I found was you have no idea what information you need to know, so it's pretty hard to search for something you don't know you need.

    ..just a suggestion.

  • #2
    I have a very similar setup.

    A couple of things.

    What is your intended use for the beans considering you have pulled them so early/light? Some kind of manual brew method filter / pour over?

    I have been enjoying these beans pulled just starting second crack for espresso.

    I aim for 14 - 16 deg / min temp rise to 150deg

    10 - 12 deg / min to FC

    At RFC I start to wind down to 3 - 4 deg / min to get me to the first snaps of second crack.



    EDIT: Sorry looking at your temps you may have well indeed been close to 2nd crack and its just the flash showing up the beans wrong or uneven roast. Even more I would recommend a much gentler / slower ramp, reaching FC around 11 - 13min, with a total roast time around 18min.


    • #3
      Hi Steve,

      Thanks for the feedback.

      I pretty much only use the beans for milk based coffee on a cafe series grinder and espresso machine, and was trying to produce a full city roast at +30 seconds past the end of rolling first crack. That was something I read on sweet Maria's website, I'm not actually sure if that's suitable for milk based coffee or not..

      As for the ramp up heat, what are you basing that on? Is that something you change from bean to bean? I'm not contesting, I don't actually know what the standard profile is and sort of just let it happen. I haven't found a guide on that particular subject and wouldn't mind to understand the theories behind it all.



      • #4
        Hi Mike
        A lot of the time & ramp ballparks here come from lots of trial and error. My corretto setup is very similar to yours and Steve's, and over the 2 years I've been roasting I've achieved almost every sort of ramp possible :-)
        While you won't notice it as much through milk, a lot of defects can be seen in the straight espresso. In general, though a bean might look brown, if the ramp has been too fast, the inside of the bean will still be raw - giving a sour flavour in the cup. If it is too slow, it loses a lot of its interesting aromatics and spice, making it taste a woody and dull. And I have enjoyed the full gamut of all these flavours personally!
        So, I fully concur with Steve. I try to do a gently ramping roast (by increasing the gun temp) that hits 1C (200°) around 13mins, then backing off slightly until the end of rolling 1C (210°) then backing off again to coast through to just at the start of 2C (225°) at around 17-18mins. This seems to be the sweet spot to get max flavour.
        But keep experimenting, cupping all your results, making notes, learn from others - and enjoy the ride :-)



        • #5
          Alright, I'll try my best to achieve those sorts of numbers.

          As for the HG itself, what temperature / fan setting are you starting on and what are you changing it to along the way?

          I was 350C/3 and then had two increases of 20C leading up to FC, then back to 350C/3 at FC
          I tried dropping the fan to speed 2 at FC but found the temp was nearing 2-3 deg/min and didn't want it to drop any further.


          • #6
            Hi Mike
            This is my printable profile, developed over 2 years, which is still my basic go-to procedure - I use this for basically every bean & blend, and it seems to work pretty consistently well. Some beans (like mexicans) I might drop a couple of degrees higher.

            It is based on a batch size of 350g, covered & insulated pan, with the Bosch HG. If you vary any of these elements in your setup, you might need to adjust your inputs to suit. Eg, if your pan is not insulated, or you do larger batch sizes, you might find the profile stretches out a bit longer than that drawn - so you might need to jump up an "ambient temp" input to compensate.

            On the RHS are my gun settings & procedures based on time or DMM readings, adjusted for various ambient roasting conditions (when it gets colder - you have to go higher to achieve the same profile). I measure the ambient with the DMM before I start - then select a 'input profile'

            Hopefully this will help get you into the ballpark - then you can tweak your roasting to taste :-)

            I'd really like to see your RM profile if you try any of these procedures - I'd love to see if the technique is as transferable as I hope it is! And to hear your thoughts on the results…


            DBC Roasting Profile Sheet Jan13.pdf

            Also - all these gun temps are on fan speed 3… :-)


            • #7
              Wow, Matt that looks great. Next roast I'll give it a go and see how it turns out.

              I'll report back once I do.



              • #8
                Ok so I tried to follow your roasting profile Matt, but found I had to abandon ship after the first temperature increase because my rate of change increased too much. For the rest of it I simply tried to replicate your profile, with whatever heat settings I required. It was basically the same intervals but using lower temps on the gun.

                The roast details:
                500g green bean batch of Peru Ceja de Selva
                Ambient temperature of 10C
                Input temperature profile used: 5-10C range (due non insulated pan and larger batch)
                Starting heat gun temp 180C
                Pulled at second crack 231C

                On reflection it looks like my first to second crack time is too short.
                Due to the higher batch size I may need to make a more dramatic heat change at FC and RFC.

                And not to neglect the whole purpose of this, the beans came out looking superb and I look forward to tasting

                What are your thoughts?


                • #9
                  Originally posted by MikeT View Post
                  Ok so I tried to follow your roasting profile Matt, but found I had to abandon ship after the first temperature increase because my rate of change increased too much. For the rest of it I simply tried to replicate your profile, with whatever heat settings I required. It was basically the same intervals but using lower temps on the gun.

                  What are your thoughts?
                  Hi Mike
                  That certainly sounds like the ticket :-)
                  There are so many variables - I'm surprised with a 500g batch you had to reduce those temps - they are based on 350g! I played with a 525g batch today and had to increase the temp by 2x ambient steps - and still not enough! But there are differences like humidity and altitude too - I roast at 1000m and far less humidity than the coast - which I'm sure plays a part.

                  But if you can work out a heat input profile that increases by 50deg at 130 and 160 and gets to 1C at around 13mins - that is basically what my procedure is.

                  If you're using the CS software, I'll load up my templates (on the other computer I'm afraid) for you to have a look - you can even then adjust the gun settings in the template to suit your batch/location etc :-)

                  But sound like you'll have a good batch to try!



                  • #10
                    Hi Mike
                    As promised, here are my RM templates FWIW for 350g batches.
                    Feel free to have a play - you can adjust the gun setting section to suit your batch size and usage quite easily by opening the files in wordpad and using find/change - that's how I do it :-)
                    I find this input temperature technique gives pretty good results with most beans very consistently.

                    DBC Profile


                    • #11
                      Hi Matt
                      Thanks again for your help. I'll try and match your template as best I can and update the input settings where necessary.
                      I'll flick it back if you like?

             for some roasting, any excuse to get out there and do some more


                      • #12
                        No worries :-)
                        Is there ever an excuse needed? LOL!

                        Just one other thing - the JPGs of my profiles might look a little different (see attached) as I adjusted the preferences in RM to reduce roast length on he graph to 20mins. So compared to the standard 30mins they look much flatter… but it will probably adjust that automatically when you load it :-)

                        Click image for larger version

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                        • #13
                          Hi Matt,

                          Well I used your roast profile for a 600g batch of Honduras Montana de Comayagua with an ambient temp of 11C.

                          I started the roast with the gun settings the same as yours, but again had to change my inputs to suit the curve.
                          After the roast profile returned to the template, I used your inputs as a guideline and guessed my way to second crack.

                          The beans turned out looking and smelling great. I'm yet to pull a shot but I'm sure they'll be a treat.
                          All in all, I think it demonstrated our units are reasonably different, but with a few adjustments can perform almost identically.


                          • #14
                            That's great work Mike
                            Look forward to hearing what you think of the results in the cup!

                            One of the things I do is use the slider in the software for power to log my gun settings (the setting of which it logs automatically) eg 15% power on the slider for 150 on the gun. That way I can record any differences in my settings that allowed me to keep to my template. Makes it easy then to adjust templates later as required :-) I'm doing that a lot currently as I'm trying to adjust power settings for larger batches…

                            Happy cupping!



                            • #15
                              Ok I'll give the slider a go next roast. I was wondering how you had that line on the screen.

                              2 part question, why do you choose to let the temp change slow down between 150-160? And to achieve that why don't you just lower the temperature rather than increasing the temperature and lower the fan speed?