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Thread: Brazil - internal scorching and ashiness

  1. #1
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    Brazil - internal scorching and ashiness

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Howdy,

    Need help.

    I am having trouble roasting a Brazil that i have previously nailed as "absolute heaven"....

    I have followed my previous profile - but repeat roasts all have an ashiness in there....stopping about 1 min before SC. I have tried a lighter roast - no good. Development after FC is about 4 mins as per the previous.

    I have tried a slightly longer dry to 150C from 5 mins to 6 mins....only a slight reduction in ashiness.

    I have noticed that when I discect some of the beans there appears to be occasionally some internal scorching.....even though i have gone easy on the heat with about a 10C/min rise in the mid phase up to FC.

    I have also tried dropping the charge temp down- do not really wan to go any lower....bottomng out at about 75C. No change.

    I am using a 2kg drum roaster.

    Got a sneaky suspicion the ashiness could be associated with some of that internal scorching.....but it only happening with the Brazils....

    Any suggestions to experiment with?

    Duct work all clean.....all other beans roasting beautifully!

  2. #2
    Senior Member Vinitasse's Avatar
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    You say you stop your roast 1 min before second crack... what temp would that be at?

  3. #3
    Senior Member chokkidog's Avatar
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    How old are the beans, what crop year and how have they been stored?
    Are they the same crop year/lot as your previously successful roasts?

    What is your drop temp? Do you soak?
    Don't rule anything out.............. try a turn temp of 60C, to me, 75C is high.
    Do you have access to a coffee bean moisture meter?

    So many questions!!
    What altitude are these beans grown at? Their density and moisture content may be playing a part here.
    And if they've dried out................

    I've had personal experience of old beans being repacked, do the greens smell fresh; herbaceous and pea like?
    Or hessian, straw or neutral?

  4. #4
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    Tried roasting various roasts between 215-223 (SC for me is about 227). Moisture loss between 15.3-15.6%

    Same beans as before - smell good and look good. It is a Brazil Cerrado.

    Charge temp I have tried is 150C and now down to just below 140C.

    I do have an acquaintance who might let me drop some beans into his moisture meter.....guess that is the starting point!

    Something happening in the development......but strange as the previous routine/profile is no longer working for it. No problems with other beans - just this one!

  5. #5
    enjoy black coffee JamesM's Avatar
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    I'm having problems with the Brazil Cerrado 'toffee' at the moment. Are you using this? My issue is mostly with tipping, I've tried a lot of changes to my roasts to prevent, but still causing problems. From corretto method to a pro drum roaster. I'm starting to wonder if it's the beans. I've decided to take the brazil out of my blend and use something else now...

    On the pro roaster I've tried 140 and 150 charge temps, short and long dry phases, etc. On a gentle ramp up the tipping isn't as bad, but still, it's there. I was using this coffee (doubt if same crop/batch but you never know!) around a year ago with very few issues, so I'm wondering if it is actually the coffee.

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    Brazil "Toffee" Cerrado it is. Friend was kind enough to analyse it for me on his Sinar - moisture 10.3% and hardness 64.

    Cupped it against a whole heap of other stuff (17 total on the table).....immediately obvious where I have been going wrong. It appears to be "operator error"....as one would suspect.
    Too long and a little too hard in the first portion. Will shorten and go a little more easy.....and see what result gives. Part of suggested solution was also a lighter roast and take it from there.

    Hope it is not the bean - was a great one when I nailed it.

    I did have what appeared to be tipping issues when my batch size went towards 500g and below (it is a 2 kg drum). At 800g batch and above the tipping disappeared even though i adjusted the charge temp to give a similar bottom out temp.

    Off for some experimenting and create a new profile for it and see if anything gives.

  7. #7
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    Tasted it today - suspicions confirmed with the help of others. Been "baking" it a bit.

    Possibly a good lesson that I have learnt out of this is to regularly "cup" the roasts - pick up roasting deficiencies a lot more quickly and accurately.

    I would not have picked some of the internal scorching as baking - but it appears that this was the case. Modified roast profile fixed problem of taste and roasting of the bean.

  8. #8
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    Reviving an old thread it appears...

    I'm getting internal scorching, on everything I roast. Whether a soft Brazil or Guat, or a hard Ethiopian or Kenyan, I get internal scorching. I'm using a coretto.

    an3_bolt: When you said "Too long and a little too hard in the first portion. Will shorten and go a little more easy" what do you mean by that? In my mind I would have thought that to go longer in the first portion you would have to go easier on the heat - not harder. And therefore to shorten the first portion you'd need to go harder on the heat?

  9. #9
    Life-long Learner DesigningByCoffee's Avatar
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    Hi Bames
    I've only discovered obvious internal scorching once with some Kenyan beans … this roast ran away at the start, so too much heat early on. See internal photo & profile…

    DBC-Macro-Kenyan-.jpg 20140325-Kenya-350g.jpg

    But I've found that slowly ramping the heat up from the turn point instead solves this issue. So I start gently, then increase gun temp by 40 at 75, 100, 125 and 150. Seems to solve the issue

    DBC-Macro-Tanz-Njiri-Wami.jpg 20140304-TanzMachare-22amb.jpg



    Cheers Matt
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  10. #10
    Life-long Learner DesigningByCoffee's Avatar
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    Sorry - duplicate post…

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    Thanks for that Matt.
    That definitely looks very different between the fast start and slow start!

    I've looked at your roasts and curves a bit and the big question I have is about baking. Most of the stuff I've read suggests that the sorts of RORs you're running - ie around 10-12*/min and 2-3 after 1st, and roasting for over 20 mins would result in baking.

    However I'm guessing you would say you don't get any baking??

  12. #12
    Life-long Learner DesigningByCoffee's Avatar
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    Not at all
    You have to remember that these were 750g roasts (except for the Kenyan - which was the problem!) are the longer times. My 'ideal' smaller 350g batch was around 17-18mins using the same ramping profile. Maybe a commercial roaster can maintain the same time for a profile independent of size, but I found that in the cup when I pushed the big batch in the corretto hard to reach the same 18mins total it was under-roasted (sour & too acidic for my liking). So this seems to be the sweet spot for my roaster dynamics without baking.

    However - the principle is still the same. You can maintain the same roast time, but get there many different ways. I find that slow start then ramping roast works best (and may well deal with the scorching) rather than hit 'em hard from the start. But all you can do is have a go, and see how it tastes!

    Cheers Matt
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  13. #13
    Senior Member Yelta's Avatar
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    Morning Bames, I run a similar Coretto to Matt and have no problems with baking either.

    I roast 750 gams per batch, start from dead cold, approx 13 mins to FC, back heat off by approx 100C depending on the ambient temp then approx another 5 mins, I stop the roast @ the first signs of SC or 225 on my DMM whichever comes up first.

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    Thanks Yelta,

    So you have the bosch heat gun? and do you run it on full boar until FC?

    I have the Ozito variable one with the red knob on the side. Does anyone have any idea whether upgrading to the bosch would help - or does the bosch just give a bit more reliability?

    I tried a 350g roast this morning following more closely to Matt's profile, FC at 14mins 185*, stop at 17 mins 198.

    One interesting thing I noticed is that I hardly get any cracks on first cracks. As in audible ones. As in I heard maybe 8 pops, and a few more that I thought might have been pops but it was hard to tell. I even did an uncovered roast at around the same timing, and still couldn't really hear any cracks at FC. When I run a roast faster, eg FC at 7 mins, the cracks are a bit more like Matt's video on youtube from a while ago, but still not quite as loud or as many...

    Any ideas on why that might be?

  15. #15
    Senior Member Lukemc's Avatar
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    No idea on the difference Bames but if your near me in sydney your welcome to borrow my Bosch variable heat gun for a week or two to compare

  16. #16
    Life-long Learner DesigningByCoffee's Avatar
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    Hi Bames
    You will get a much louder crack if you go hot into first crack hot. And also different beans. But the strength of the cracks is no guarantee of good taste - if you put more heat in you will get a more aggressive reaction in response

    FWIW the Bosch gun has been the best investment I've made. I used to run a 2-speed Ryobi, but the Bosch is so accurate (absolutely linear temp rise - I've logged on the DMM once to see!) that you really can tune a roast to almost any profile and vary elements like roast length by 20-30secs or so. Like a swiss watch.

    In terms of temps - the Bosch is a 650 gun, but I only use the range from about 350-550 really - so not flat out. After the turning point I start at around 350 and increase the temp by 40 every 25 on the DMM until 150 to give me the ramp, then leave it there till first crack, then slowly drop back down to second crack.

    Everyone has different ideas about their favourite profile - the trick is experimenting and finding yours. When I've roasted hard from the start, I found it carried too much acidity for my tastes and tasted quite aggressive, while the ramp gave more sweetness for espresso. Horses for courses!


    Matt
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  17. #17
    Senior Member Yelta's Avatar
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    Behmor Coffee Roaster
    Quote Originally Posted by Bames View Post
    Thanks Yelta,

    So you have the bosch heat gun? and do you run it on full boar until FC?

    I have the Ozito variable one with the red knob on the side. Does anyone have any idea whether upgrading to the bosch would help - or does the bosch just give a bit more reliability?

    I tried a 350g roast this morning following more closely to Matt's profile, FC at 14mins 185*, stop at 17 mins 198.

    One interesting thing I noticed is that I hardly get any cracks on first cracks. As in audible ones. As in I heard maybe 8 pops, and a few more that I thought might have been pops but it was hard to tell. I even did an uncovered roast at around the same timing, and still couldn't really hear any cracks at FC. When I run a roast faster, eg FC at 7 mins, the cracks are a bit more like Matt's video on youtube from a while ago, but still not quite as loud or as many...

    Any ideas on why that might be?
    Yes I do have the Bosch variable speed heat gun, no I don't run it flat out, right now because the weather is cooler I start on medium fan, temp 550 up to first crack, then drop the temp by 100 up to the finish.

    As a matter of interest FC on most of my roasts is very noticable and goes on for quite some time.



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