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Scorching..... and how to prevent it!

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  • Scorching..... and how to prevent it!

    Hi guys,
    I'm a new member from the UK who has just discovered this amazing group - thanks for letting me join you.

    I'm a long tiime coffee fan but have just entered the wonderful world of home roasting.
    After a few weeks playing with a pocorn popper, and producing some quite drinkable roasts, I decided to bite the bullet and got a Behmor 2020SR.
    I had done quite a lot of research but realised quite quickly that much of it was downright missleading as it was based on 110v Americal roasters and consisted mainly of complaints that the ****** thing wouldn't get hot enough!
    My first roast was a 100g batch of Guatemala SHB which I had roasted in the popcorn popper and enjoyed drinking. I followed the advice in the manual (that might have been my first mistake) and did a P1 Auto roast - got a distinct 1st crack but then things got balistic pretty quickly. I ended up with a very even roast but the beans were very dark and, after a couple of days, very oily; I suspect it was well into 2nd crack before I ignored the manual and hit COOL. It actually tasted OK as an espresso but the roast/burnt flavour was a bit too much for someone who usually drinks medium roast. As a V60 it resembles a Starbucks Americano - not good!
    My second attempt was using P2 Auto and the power drop at about 5 minutes seemed to help keep things under control and I stopped it before it got too dark. Still a bit darker than I would like, developed a little oil after a couple of days but much more drinkable.

    At this point I discovered Coffee Snobs and realised that you guys are also using 240v machines which, as Andy points out in a couple of posts, are very different animals to the 110v versions.

    I placed a thermocouple in the chaff tray and decided to record the A, B and Probe temperatures during my next roast. Having spent hours reading old posts in the Behmore Roasting Approaches thread I decided to try out some of your methods - although I'm not sure if the old 1600 machine is essentially the same as the new 2020SR?

    Next roast was an Ethiopian washed Djimmah which I roasted using Andy's basic method; Auto P1 to 1st crack and then P2. This worked pretty well and resulted in a very even medium dark roast BUT with a tiny amount of scorching.

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    I tried two other 'recipes' - a) Auto P1 dropping to P4, P2 at 1st crack then P3 before COOL on the same Djimmah beans:
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    and b) P4 raising to P5 at end of drying, P1 at 1st crack for 30s then P2, P3 and P4 at 30s intervals. This was suggested for a Brazil natural which was the coffee I used. I actually hit COOL before going to P4 as it was getting a little dark:

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    Both of these roasts look pretty good to my inexperienced eye BUT........ show some scorching.

    Finally...... to my plea for help!
    I have read lots of seemingly conflicting information about the causes of scorching but, once again, most of it relates to commercial roasting or to the USA 110v home roasters.

    The graphs show the second Djimmah roast (top) and the Brazilian Natural roast. First crack is the yellow box and the blue arrow shows when COOL was hit (also end of tan arrow)

    Any suggestions as to how I can reduce the scorching would be great as my brain is overheating as much as the beans!

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  • #2
    Welcome. I think the first thing you should try is a 200g batch size.


    • #3
      Thanks flynnaus - I should have mentioned that the last roast - The Brazil natural - was 200g. I had wondered if the 100g batch size, which Behmor insist you should 'learn' on, was just making things happen faster than I could follow or respond to - probably another consequence of the advice being aimed at 110v users?


      • #4
        Brazilian beans are lower density and so need a gentler roast profile. I should add that I haven't roasted Brazilian on a Behmor before. Yes, they look a bit dark but photos can be deceptive especially when viewing beans against a white/light background.
        Andy recommends 200g batches for better results



        • #5
          Agree with Flynn - 200g (and also 350/400g) batch sizes seem to work better on the Behmor in my opinion. 100g just gets away from you too quickly and a lot less margin for error.

          Roasts look pretty decent for the first few attempts. Also keep in mind most of the ethiopians are natural processed so individual beans will vary quite significantly and look mottled.

          Personally I didn't spend much time using the auto roast profiles and moved quickly onto custom profiles - changing the heat input in the last quarter of the roast or so. I find that very little heat is needed once you hit first crack as the process becomes exothermic and the temperature can run away for a few minutes. Depending on the bean I add a little extra heat once most of the way through first crack - but thats part of the fun working out a good profile for each bean.

          As always let the results in the cup be your ultimate guide. Ideally try different profiles side by side to see if different profiles bring out different flavours that you do or don't like and try to replicate those you do like!


          • #6
            Hi AstroMike,

            I think I'm probably at a similar stage of Behmor 'evolution'.

            I roast weekly and am iterating through multiple recipes and profiles - in reality I think that there are a few too many variables trying to nail both but its fun!

            I definitely agree with more bean mass - my standard load is now 350g.

            While I haven't standardised on a single roast profile I've tried all the inbuilt auto profiles and now operate a hybrid model that I plagiarised off someone here on CS (sorry I cant remember his name so can give him credit)

            400 [A] [P1] until 1C
            [C] [P2] [D] for 2 mins
            [C] [P3] for 2 mins
            then cool

            typical moisture loss is 16% - 17%

            It is critical to keep notes both roasting and cupping so you can build on successes and avoid repeating errors.

            I'm a roasting novice but still drinking some fantastic coffee - if I'm honest I think mostly thanks to the fantastic quality beans here on BeanBay!



            • #7
              Hi SanderP - its nice to hear from someone on the same journey! Your roast profile is pretty close to what I used yesterday but with 200g. It looks pretty good with 14.1% moisture loss.

              As I said in my first post, I originally got suckered into following Behmor advice online without realising that 99% of it comes from Americans using the 110v system. Most of them are using 'workarounds' to increase heat which is totally inappropriate for those of us using 240v machines on stable supplies - mine is rock solid at 245v.

              There must be quite a few Behmor users in the UK but there seems to be very little advice online from them - might be because the machine has only recently been approved for use here?

              Fortunately I then discovered the CS forum and realised that you guys are using the same machine running at 240v. Even better, there are lots of experienced users willing to share their successes and failures.............. just what I need!

              The most frustrating thing for me is that the manual included with the roaster is actually a recipe for failure. Although it has the 2020SR model name and uses grams rather than pounds/ounces on page 1, most of the rest of the manual is obviously aimed at users of the 110v machine. I wonder if they have just changed the model name and used the American manual?

              Being a bit naive I followed their advice to pre-heat and use 100g of beans.............. the result was a fast, overheating roast which was very hard to control. As instructed, I pressed C at the start of 1st crack BUT was deep into 2nd crack within half the 'Rosetta Stone' period and pressed COOL 30s earlier than advised. After cooling I looked at the very dark beans which most of the online advice says are impossible to achieve with the Behmor 😀😂😀

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              The manual insists that this is the easiest way to produce a foolproof roast and the best way to learn to use the machine - nope, not from my experience!

              Now I'm using 200g roasts I hope that things will improve - in any case, I've just enjoyed a really rich espresso made with the Guatemala SHB from my 2nd roast and pulled from my refurbished 1995 La Pavoni Europiccol so things could be worse!
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              I agree with you about the importance of bean quality. I bought 1Kg of 'cheap' beans to play with on a popcorn popper and used them for my first couple of Behmor roasts. I now have about 5 200g samples of different beans from a more reliable source so I should find something I like and can enjoy.

              I have a HeatSnob on order - currently sitting in Melbourne airport waiting for a plane to the UK (been there, got the t-shirt) - so that will add to the fun.

              Thanks to all you guys for the good advice.


              • #8
                Astro Mike welcome... I have a behmor and a gene cafe and I think the biggest improvement I made was externally cooling the beans. The slow cooling system on the behmor (and gene) means you have to second guess where your roast is going to finish. There's plenty of info on the forum regarding external cooling.