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Thread: Can you judge a bean by its (roast) colour?

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    Member C8H10N4O2's Avatar
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    Can you judge a bean by its (roast) colour?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi there!

    I am really confused!

    In my vain effort to find more info about home roasting (Avi - your posts rock by the way!!) I came across a chapter in the Coffee Basics book by Kevin Knox where he vehemently claims that "you cannot accurately gauge the roast of a bean by its colour, nor the quality of a coffee by its degree of roast. Judging roast by colour is just plain dangerous"

    Now I know with my Imex, because it is so loud, I have to rely on my senses a lot more - especially watching the colour of the roast.

    I am really confused by this claim because I thought that judging by colour was a fundamental part of roasting?

    Can anyone set me straight?

    Anne :-/

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    Senior Member fatboy_1999's Avatar
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    Re: Can you judge a bean by its (roast) colour?

    Anne,

    I would agree that you cannot always judge a roast by its colour, however if you are the one roasting them, the rules change a bit.
    There are so many variables whilst roasting, it takes a lot of experience to hit the same (or desired) level of roast.

    If you use the Imex regularly and you get to know the roast profiles of the beans you are using, it is possible that you will roast darker than others but the flavour will not be the same as a dark roast of the same bean from a different method.

    My advice, if you are doing your own roasting and using the same method each time, judging by colour is a very important aspect.

    Brett.

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    http://www.coffeereview.com/interpret_coffee.cfm

    Whilst not the sole factor, as far as I know (and thats not very far :)) colour is fairly heavily relied upon for determining roast level:

    "Degree of roast can be measured with some precision through the use of a specially modified spectrophotometer popularly called an Agtron. Agtron readings range from #95 (lightest roast) through #10 (darkest common roast) in intervals of ten." http://www.coffeereview.com/interpret_coffee.cfm


    Stephen

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    Senior Member robusto's Avatar
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    Re: Can you judge a bean by its (roast) colour?

    C8H10n402 -- Can I call you C8 for short! The judgement comes from the taste, and in my experience that has been very much related to the colour. So far, Ive only thrown out one 150 gram batch of roasted beans, very early in the piece. The very light colour didnt look right to start with. The taste of grain confirmed my suspicions, and into the bin they went. Later, going to the other extreme, a near-black roast, while loooking the part of many supermarket beans, looked encouragingly OK. But alarm bells when I ground them. Instead of nicely clumping into the portafilter like soft powder, they shot out and richochet at speed all over the bench and floor. The subsequent taste proved them very much over-done. I am now confident the roast has been a success the moment piping hot beans are emptied into a cooling colander -- going by their looks alone at that point. A medium/dark brown colour has been a positive indicator of taste for Colombian, Ethiopian, Dominican and Guatemalan. Of course, different people have different tastes, and different beans prefer different roasts... but the colours should still be indicative of all that.

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    Re: Can you judge a bean by its (roast) colour?

    Thanks for your responses guys!

    So would Kevin Knox be referring then to maybe recognising the quality or origin of the bean you are roasting because, depending on whether the beans are high or low grown, then they may be moister and denser, be slower to roast (ie: Colombia/Sumatra/Sulawesi), and will absorb higher temperatures thus roasting very differently to a low grown bean??

    So, the beans may be of different origins but have the same green weight (150gm) in the same roasting conditions (Imex) and have been roasted for the same time (8.5-9min) but may not necessarily show the same agtron colour for that roast time and not match the roast profile/taste for that colour because of its origin?? (boy that was a mouthful!)

    Oh heck - I think I will stick to my guns and continue with judging by colour and taste because thats what Ive been doing all along!!

    Anne *;)

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    Super Moderator Javaphile's Avatar
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    Re: Can you judge a bean by its (roast) colour?

    The taste of the coffee should always be the final arbitrator of how to roast a particular bean. Unfortunately at the time we pull the roast we have no way of knowing what that batch of beans tastes like and so we have to look to other indicators to determine the degree of roast with color being but one of them.

    What factors you use to determine at what point to stop your roast will be mainly determined by the equipment you are using.

    In the high end roasters (i.e. commercial roasters and custom built home units) the temperature of the beans themselves are monitored and this is the main factor that determines when the roast is pulled.

    As home roasters with a bit less technology in our roasters we generally dont have this option available to us and as such must find other ways of determining when to stop our roasts. As part of this we need to have a good understanding of just what the roasting process is and what is happening to the beans as they roast (http://www.coffeesnobs.com.au/cgi-bin/yabb/YaBB.cgi?board=roasting;action=display;num=1114856 735;start=6#6).

    When using a BBQ set-up you cant see the beans and on most set-ups you cant pull a bean sample to see what they look like. Because of this we have to find other ways of determining when the roast is done. If the BBQ is set up in an area where the ambient conditions (air temp, humidity, and wind) remain constant the time of the roast can be an accurate gauge. For most people however this is not the case and they must turn to judging the degree of roast by the sound of the beans and the smell of the smoke. When roasting beans to, and into, 2nd crack then sound is the primary determining factor in when to pull a roast and is relatively easy to do. Where it gets tricky is when you want to pull a roast before it reaches 2nd crack. This is where smell becomes the primary determining factor in when to pull a roast. As the beans approach 2nd crack the amount of smoke will increase and it will start to take on a sweet smell and then a burnt sweet smell with the smell of the smoke making several changes very quickly as you approach and then enter 2nd crack and with the volume of smoke increasing as well.

    With some homeroasting set-ups you can see the beans and hence can then use their color in addition to their sound and smell to determine when to pull a roast.

    With some set-ups, such as roasting with a heat gun, you have to rely more heavily on your senses to tell you when a roast is done. Due to variability in ambient conditions every roast will be slightly different in how long it takes and hence time alone cannot be used.

    With roasters that provide a consistant physical environment roast to roast (most commercially made roasters as well as many homemade rigs such as a popcorn popper) time alone can be used if the ambient environment surrounding the roaster and the line voltage are held constant. But even with these set-ups one can not rely totally only on time unless the beans are stored such that they remain at the same moisture content. If the moisture content of the beans change then your roasting time will also change.

    In the end its a rare roaster who is able to keep all the environmental, bean, and roaster variables constant and use time alone to determine when to pull a roast and so deciding when to pull a roast becomes a very subjective thing. For this reason most commercial roasters take the beans into 2nd crack as this is an easily identifiable stopping point. This gives them a consistant batch-to-batch roast. However, as true coffee snobs were more concerned with getting the best cup possible from our beans rather than sacrificing taste just so we can pump out identical roasts.

    As most beans sweet spot is prior to 2nd crack and we do not have full control over all the environmental variables we have to make a judgement call on when to pull a roast based on our senses. The color of the bean is a good indicator, but it is just one such indicator and should not be relied upon to the exclusion of all others. Every variety of bean will produce a slightly different color when roasted and as such you cant use the color of one variety to determine the roasting level/color of a different one. When comparing color when roasting the same variety you can use color to determine when to stop the roast but youd better be quick about it as in the 15-30 seconds it can take to determine the color of your pulled sample you may have just gone too far in the roast. Things happen very quickly as the beans approach 2nd crack and 30 seconds can easily make the difference between an awsome roast and one thats barely drinkable, or even totally undrinkable.

    In the end it comes down to training our senses to recognize the different points in the roast and determining what roast level works best for which beans in accordence with our individual tastes. To help this I strongly urge people to keep a log (heres a nice one http://www.coffeesnobs.com.au/cgi-bin/yabb/YaBB.cgi?board=roasting;action=display;num=1113135 726;start=0#0) of every roast they do. Recording not only the type and amount of beans roasted but also the ambient conditions, any change or variable in the roasting proceedure and equipment, and most importantly your notes on what the roast sounded, smelled, and looked like. Writing this information down helps fix it in our minds and gives us a written database (make sure you keep a backup!) to refer to later rather than relying on our faulty memory.

    I hope this helps. :)

    Java "Rambling on again" phile

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    Avi
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    Re: Can you judge a bean by its (roast) colour?

    Hi Anne,

    Thank you very much for your kind words, much appreciated :)

    From my experience, colour is a very difficult and variable parameter by which to judge the progression of a roast. There is a great degree of variation in the roast colour of different coffees, when at the same roast point. For example, the Ethiopean Yirgacheffe looks quite dark when I stop the roast just shy of the 2nd crack, while the Sumatran Mandheling takes on a similar shade of colour at about 30s into the 2nd crack.

    As I roast my coffee with a heatgun, and a popper, I use a combination of sound (cracks), smell, smoke & sight (bean colour and appearance). With experience I get a feel for each coffee or blend, and how it roasts. Once I have this "feel", it is relatively easy to reproduce the roast.

    That being said, the way in which the weather is bouncing around in Melb has been playing havoc with my roasts. I did two roast batches yesterday - one was overdone, and the other was underdone. Go figure!

    My advice is - pay attention to the "rules" until you can fly solo. Then throw the rule book out, and make up your own.

    Avi

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    Member C8H10N4O2's Avatar
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    Re: Can you judge a bean by its (roast) colour?

    Sounds like a mighty fine plan Avi!

    I am currently enjoying one of your suggested blends of *Brasil, Sumatra and Yirgacheffe.

    And Javaphile - I could not have asked for a better response! Thank-you so much for taking the time to write such a detailed explanation!! Much appreciated!

    Anne *;D

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    Avi
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    Re: Can you judge a bean by its (roast) colour?

    Excellent! Can I ask what coffees you currently have in the cellar? The many knowledgeable members of this forum might have some great blend suggestions for you.

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    Re: Can you judge a bean by its (roast) colour?

    I have: Ethiopian Yergacheffe
    Ethiopian Harrar
    Columbia Excelso
    Sumatra Mandheling
    Kenya AA
    Kenya PB
    Peru
    Brasil Monte Allegre
    PNG Kimel



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    Avi
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    Re: Can you judge a bean by its (roast) colour?

    Hi Anne,

    Unfortunately I havent tasted many of your coffees, so I dont have any specific blend recommendations. So, heres what I suggest:

    1. Pick a "character" coffee. From what I can tell, these fit the bill - Yirgacheffe, Harrar, Kenya & Peru.

    2. Add a milder "base" coffee. Start with proportions of 60%/40% in favour of the base coffee. These fit the bill as base coffees - Brasil & Columbia.

    3. How does it taste? Does it work? For me Columbians dont work as a base. I often use both Brasils (> 35%) & Columbians (< 30%) together in the same blend.

    4. Once you have worked out a base for your blend, add a "body" bean. These may fit the bill as body coffees - Sumatra Mandheling & PNG Kimel

    See how they all dance together. Does it all work? Do the proportions need to be tweaked? Does it need a darker or lighter roast? Does it have enough character? What about the aftertaste - does it linger? Is it complex enough? etc, etc.

    You can continue to finetune the blend until the cows come home :)

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    Super Moderator Javaphile's Avatar
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    Re: Can you judge a bean by its (roast) colour?

    Not knowing how much experience you have with roasting may I put forward the thought that if youre new to it you might want to roast up the beans as single origins before moving onto preroast blends.

    Roasting as single origins allows you to get a better feel for how each bean roasts and what characteristics are brought out at what point in the roast. It also allows you to taste the coffee as an SO giving you a better idea of how it may fit with other coffees in a blend.

    Roasting as SOs also has the added bonus of allowing you to try many different blend combinations with-out going through 10kg of beans as you can do post-roast blending and try dozens of blends where normally you may only get 3 or 4 from that amount of beans. :)

    Java "Aaahhh...Smell that smoke!" phile

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    Re: Can you judge a bean by its (roast) colour?

    Thats what I have been doing :)
    I roast 3 or 4 different beans as SOs then mix them in the grinder... seems to be working well so far!

    clarexican

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    Re: Can you judge a bean by its (roast) colour?

    Quote Originally Posted by Javaphile link=1115521013/0#5 date=1115577433
    As most beans sweet spot is prior to 2nd crack and we do not have full control over all the environmental variables we have to make a judgement call on when to pull a roast based on our senses.
    Hi Java,

    Tried your suggestion above with my most recent roast of four different varietals and I have to say, that the resulting brews from beans roasted at various stages before 2nd Crack.... 30, 20 and 10 seconds (as good as I could estimate on the day) proved to be much more flavoursome and sweet than with my usual roast of about 10-20 seconds past 2nd Crack.

    I must admit, that from lurking on a.c. and CG for a time had more or less encouraged me to consider that the 2nd Crack milestone was one that should always be passed. This seemed to be supported by some of our own respected Aussie commercial roasters whose business I used to patronise before taking up home roasting.

    In short, this seems to have opened up new doors of opportunity for me to try with home roasting that seems to have the potential to take my coffee consumption hobby to a higher level. Most grateful Java, for your insightful contributions. Onward and upward,

    Cheers,
    Mal.


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    Super Moderator Javaphile's Avatar
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    Re: Can you judge a bean by its (roast) colour?

    Hey Mal,

    Im glad my suggestions proved useful to you. Now you can enjoy the full flavor of your beans with all their subtle nuances and tastes with-out their innate flavors being masked and dulled by the flavor of the roast. :D

    If you havent already tried it might I suggest, once youve tasted each individualy, blending the different roasts (of the same beans) together. I have found that this gives the cup added depth and is what I do on a regular basis. The only time I dont do this is when theres a roast that exhibites some special quality that I want to drink as a (as Ive come to call it) Single Roast SO, as oppossed to a Blended Roast SO. :)

    Java "Loves to experiment" phile

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    Re: Can you judge a bean by its (roast) colour?

    Quote Originally Posted by Javaphile link=1115521013/0#14 date=1116268163
    Hey Mal,

    Im glad my suggestions proved useful to you. Now you can enjoy the full flavor of your beans with all their subtle nuances and tastes with-out their innate flavors being masked and dulled by the flavor of the roast. :D

    Java "Loves to experiment" phile
    Hi again Java,

    Actually, your advice was more than just useful. The simple act of applying your suggestions has had the effect of opening up the whole roasting process to a new level of appreciation for me. Its almost as if a "veil" has been lifted or some kind of Taste Mask, for want of a better description, has been obliterated.

    I now cant wait to retry some of my favourite beans using the enlightened roasting approach, and am sure it will be just as revealing as my most recent attempts. Will also try your suggestions of blending identical beans from different roast profiles and see what that does for me. Its a whole new world again. As we say here in Aussie Java, your bloods worth bottlin. Now, if I could just find a way to drink my way through the current roast batches more quickly so that I can experiment some more...

    Cheers Java,
    Mal.

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    Super Moderator Javaphile's Avatar
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    Re: Can you judge a bean by its (roast) colour?

    Hey Mal,

    Thank you for your kind comments. Now stop it, youre embarassing me! ;)

    Ive always considered Rules to be just basic guidelines to be used to help one establish what works best for them, rather than to be adhered to inflexibly. This isnt to say that the rules are ignored, on the contrary, one must first understand the rules and most importantly *why they are what they are before one goes and breaks them. Once one understands why the rules are what they are it allows one to make an educated guess at what to change to customize the end result to ones individual tastes/desires.

    I learned at an early age that what works for others didnt always work for me, in fact they rarely worked for me. Unbeknownst to the people around me I was legally blind from birth through age 6. This was discovered in the 1st grade health screening when I couldnt even see the eye chart, much less read what was on it. (It turned out that my mother had German Measles early in her pregnancy with me.) This necessitated that I find my own way to do things as what worked for the people around me obviously wouldnt work for me. Thus I got started down my path of breaking The Rules to find what worked best for me and while not ignoring the rules they were used simply as a starting point rather than as the end-all and be-all. So here I am some 40+ years later still making my own rules. ;D

    Java "Veil Lifter" phile

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    Mal Dimal's Avatar
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    Re: Can you judge a bean by its (roast) colour?

    Hi again Java,

    As a Home Roaster, Im an absolute newbie really and still finding my feet as it were. Im a bit limited in my dexterity and strength after a series of strokes, particularly my left side, which is a good thing since Im right-handed. This kind of limits me to relatively hands-off methods of roasting so far.

    Well anyway, the short story is that Ive only really tried Popper Roasting so far and up until I modified the popper to allow me the flexibility of stretching my roasts out a bit, I was more or less at the mercy of the poppers own thermodynamics, which varied quite a bit depending on ambient conditions at the time of roasting. Sometimes, in fact quite a lot, the 1st and 2nd cracks occured so close together it was impossible to tell when one ended and the other started. Needless to say, my roast attempts at these times were very hit and miss, mostly miss.

    With the advent of control over the fan speed now though, I can stretch roasts out to about 12-13 minutes and the improvement in the quality of the brew is really very pronounced. I would say that a similar leap in quality at the cup has been achieved by paying much closer attention to the timing of the roasts before 2nd Crack.

    I will continue to play around with the roast timings now using your suggestions as a guideline to see what else I can learn from the process. My next project is to build a Turbo Oven/Stir Crazy type of Roaster except that I will be using a modified heavy based frying pan and home-made stirrer mechanism using parts from a number of devices that I never quite got around to throwing out, you know.... might come in useful one day. Wont give up on the popper just yet though, still plenty to learn about using this for a while to come. Its only short-coming really is the quantity of beans that I can roast in a session. Not so much for our needs here at home but for when I roast up packages as gifts for friends and rellies.

    Well, Ive got another roasting session coming up tomorrow so will see what I can do with some of my old favourites and some new Decaf that I have never tried before. Really wierd looking beans those... look like they have already spent some time in a roaster but I know that it is just the Water Process effects on the beans that turns them that colour. Will be an interesting session. Well, got a few more chores to do before hitting the hay tonight so better get started as they say. All the best Java, and

    Cheers,
    Mal.

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    Super Moderator Javaphile's Avatar
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    Re: Can you judge a bean by its (roast) colour?

    Hey Mal,

    ...using parts from a number of devices that I never quite got around to throwing out, you know.... might come in useful one day...
    <Javaphile looks around at the piles surrounding him> I wouldnt know anything about stuff like that! ;) ;D ::)

    Im still toying with various designs in my head here for my next roaster. My current one does a great job, but the batches are just way too small, especially at gift time. Im also trying to convince an old time commercial roaster here to part with one of his old roasters but so far hes very reluctant to do so, apparently (per one of his employees) fearing the possible competition. I had a laugh He knows Im just a home roaster, but hes also aware of all the equipment I have and that really the last thing I need that would enable me to open up my own shop is an appropriately sized roaster. With-out that roaster Im not likely to open my own cafe, with it how-ever I would almost *have to open my own place. ;D ;D

    Good luck with your project! :D :D :D

    Java "Inventors R Us" phile

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    Re: Can you judge a bean by its (roast) colour?

    Hiya Java,

    "Open your own Cafe"! Wow, thats a big step-up from a dedicated CoffeeGeek. As much as I love coffee, I dont think I could turn around and evolve it into a business, I just enjoy drinking it too much. 8)

    I think if I had to do it for a living some of the gloss might rub off but then again, you would probably get to meet a lot of interesting people and that might be worth the trade-off? I could just imagine it though if you did, you wouldnt be able to leave anything well enough alone, there would always be little tweaks, adjustments and mods to make something work that little bit better or make the coffee taste that little bit richer. You might be too busy tweaking to sell enough coffee to pay the rent. :o Probably have a great time though. :D

    Ill just stick to my own personal little patch here at home and only worry about which beans Im going to roast next, and how.... should I go with the Yemen Mocha or the Yirgacheffe? Hmmm.... decisions, decisions. ;D

    Cheers Java,
    Mal.

  21. #21
    Super Moderator Javaphile's Avatar
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    Re: Can you judge a bean by its (roast) colour?

    Quote Originally Posted by Mal link=1115521013/15#19 date=1116511078
    ... I could just imagine it though if you did, you wouldnt be able to leave anything well enough alone, there would always be little tweaks, adjustments and mods to make something work that little bit better or make the coffee taste that little bit richer. You might be too busy tweaking to sell enough coffee to pay the rent. :o Probably have a great time though. :D...
    I had a laugh Yall are getting to know me I see. ;D ;D ;D

    If I were to do this Id most likely do it in a small town. Ive had a couple offeres from local resturants to put my machines in their business and sell Java. Ive not pursued them however as until I have a larger roasting capacity itd be far too much work, and if Im using somebody elses roast, why bother. Plus Im looking at selling my house and business and retiring here in the next year or two.

    At this point my plans are to buy a deepwater sailboat and cruise where-ever the whim takes me. Now Ive just got to figure out how to bring my beloved Java with me. Due to their power requirements I dont see bringing my current machines with. I have no desire to be running a generator all day long just to keep the espresso machine hot so Im looking at perhaps one of the older gas-fired manuals. Either that or something along the lines of a Pavoni lever that can just be turned on when you want a cup and quickly heated up and then powered down with-out using too much power. Barring some major advances in wind or solar power it looks like this is the path Ill have to take. Ill be bringing my little electric roaster with but itll be a back-up to the BBQ. :)

    Java "Always tweaking" phile

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    Re: Can you judge a bean by its (roast) colour?

    Behmor Coffee Roaster
    Quote Originally Posted by Javaphile link=1115521013/15#20 date=1116521217
    Plus Im looking at selling my house and business and retiring here in the next year or two.

    At this point my plans are to buy a deepwater sailboat and cruise where-ever the whim takes me.

    Java "Always tweaking" phile
    Now, thats what I call a geat set of plans. 8)

    Mal.



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