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Thread: Time between first and second cracks...

  1. #1
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    Time between first and second cracks...

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Ive been working on trying to achieve 5-6 minutes from first to second cracks and it has been quite difficult in controlling the temps to achieve this especially now that its cold. Its either been the roasts run away too quickly despite attempts at temp control or it stalls and takes too long... Which side is it better to err on? To have the time between the 1st and 2nd a bit too quick, or a bit too slowly if you had to choose a lesser of the 2 evils?

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    Senior Member redzone121's Avatar
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    Re: Time between first and second cracks...

    I have been using a cheaper heat gun and this has made things different in terms of stretching the time from FC to SC. I am only getting 3-4 1/2 mins, but the coffee has been great.
    When my first heat gun was not working properly I ended up with a 21 min roast and the taste was too bright for our liking (this could be due to taking too long to FC) not just the total length of roast.
    Of course this is not to say all 21min roasts are not good, but for me I would think a little shorter rather than a little longer.
    CB

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    Senior Member greenman's Avatar
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    Re: Time between first and second cracks...

    It is a little tricky stretching from 1st to 2nd crack in 6 minutes, I manage to get pretty close most roasts but in summer when it was 50C in my garage a couple got totally away from me (2mins). The beans tend to race along just after 1st on their own and then ease off, I usually ease back the heat gun at the first sign of 1st crack and keep an eye on the DMM constantly and make height adjustments as I go.
    Some of the highgrown harder beans are trickier to roast as well.
    But its all a learning curve a heaps of fun...............................

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    Re: Time between first and second cracks...

    Ive been using the Roast software and that has a live rate of rise per minute reading which is great and helps the roast monitoring a lot more than just the DMM. Even then I struggle with keeping it under control.

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    Senior Member Stan's Avatar
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    Re: Time between first and second cracks...

    I found the roast monitor great with the Live rate per minute it helped even though, through other errors the roast went a little longer than I expected. But it enabled me to back off the heat fairly accurately to arrive at the point I wanted for second crack.

    However if you havent got a lap top you can have sitting next to you it would be difficult.

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    Mal Dimal's Avatar
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    Re: Time between first and second cracks...

    Hi Guys,

    You also dont want to forget the importance of controlling the ramp to FC either. Just as important as the ramp between FC and SC and in some case, even more important. I know we try to be helpful with ballpark profiles to help you get started but it is really essential to get into the habit of developing profiles for yourself with small batches of 80-100g in a modified popper or similar so that you can control the profile using air-flow control (by partially blocking the exhaust for instance). Without the use of a Digital Thermometer or Datalogger it is still shooting in the dark a bit, but so long as youre really observant, record everything including subsequent cupping notes, youll discover profiles for various bean types that will literally, blow your socks off..... ;)

    Cheers,
    Mal.

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    Re: Time between first and second cracks...

    I try and slow the roast down as much as I can between 1st & 2nd crack, aiming for an increase of around 3C a minute. I think its best to keep it slow but with the temperature always increasing.

    What helped me was one of those drill presses. It allows me to lower and raise the heat gun ever so slightly whilst watching the thermometer (as well as the beans of course, gotta keep one eye always on them beans). ;)

    Aldies sell them cheap at $15. Still I had to spent a little time modifying it to get it right.

    A Digital Thermometer is essential to roast consistency. As Mal said you are "shooting in the dark" without it.

    Their are so many variables when it comes to coffee. Minimizing the variables is the key to good consistent coffee I reckon.


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    Sleep is overrated Thundergod's Avatar
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    Re: Time between first and second cracks...

    Quote Originally Posted by U4koffee link=1213594195/0#6 date=1213778347
    What helped me was one of those drill presses. It allows me to lower and raise the heat gun ever so slightly whilst watching the thermometer (as well as the beans of course, gotta keep one eye always on them beans). ;)

    Aldies sell them cheap at $15. Still I had to spent a little time modifying it to get it right.
    A pedestal fan base retrieved from a kerbside cleanup pile does the same job for $0.

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    Re: Time between first and second cracks...

    Quote Originally Posted by NewToEspresso link=1213594195/0#0 date=1213594195
    Which side is it better to err on? To have the time between the 1st and 2nd a bit too quick, or a bit too slowly if you had to choose a lesser of the 2 evils?
    I have been using a Corretto for not very long and have the same question.

    The set up that I have is fairly controllable.

    On a CoffeeGeek forum someone stated that extending between FC and SC increases the varietal notes but extending it too far starts to distroy them.

    Is there anyone out there who can shed some light on this?

    After learning the "lag" heat time to the amount of beans, FC temp and SC temp with my Corretto setup I have found I can heat up at any ramp speed (upto 50C per minute), predict the FC time within 20sec, extend/shorten the RFC time, hold the bean temp anywhere in between FC and SC (actually any temp).... forever, predict SC within 20sec and extend/shorten RSC.

    This leads me to the question of what difference does it make to ramp slower/faster to FC/SC?
    Does it make any difference in slowing the rolling cracks down?
    Should you ramp quickly/slowly to different temps other than crack temps?

    And like the question posed on the CoffeeGeek site does anyone know WHY? "Does it allow more caramelization? *Does it preserve the internal structure of the bean and therefore (fill in the blank)? *Does it have some effect on the Maillard reaction?"

    There seems to be a lot of knowledge in things like wine making, beer brewing, cooking etc but not much in coffee roasting.
    Most answers given tend to sound like when my mother used to say "because I said so"(without my mothers arrogance). No reason, just is. :-[

    Surely there is a pro roaster out there that has done all the experiments and has some answers. I only drink 2-3 shots a day, Ill probably be six foot under before I could work some of it out!

    Any guidance?

  10. #10
    Senior Member GregWormald's Avatar
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    Re: Time between first and second cracks...

    (I think) Ive been slowing the rise to first crack by gradually raising the temp of the Gene Cafe. Its only stretching the rise by a couple of minutes over a straight 230 set temperature but I like the results.

    Different beans react differently to this, but a time of about 13 minutes (give or take) seems to work well. At rolling first crack I lower the heat and get the beans to coast into second crack about 5 or 6 minutes later, give them 20 or 30 seconds into second and then cool. Without the lowering of the temp at first crack, second crack was only 2-4 minutes later, and (to me) the flavour was underdeveloped.

    This works for me--giving me a nice rounded smooth flavour, with some acid to cut the milk but not so much as to make the ristrettos sour. Much of the floral or fruit notes become mixed with chocolate here, and that also is to my taste.

    The 230 set (with a reduction to 220 at first crack) left the straight ristretto a bit acidic for me.

    I only make ristrettos--straight or in piccolo latte form.

    I hope this helps.

    Greg

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    Re: Time between first and second cracks...

    Gday "bassway"...

    Ive been using a similar process to the one described by Greg above for the last few years now (probably with more variability depending on bean/crop), having arrived there purely by a process of trial and error and using my palate as the judge.

    As for why this works for me and other methods Ive tried work less well, I dont really know as Im not a chemist but the Coffee Research website has some excellent info on a lot of this with links to other information sources as well, so I would recommend some time spent soaking up some of that knowledge.... Might help to sate your curiosity a little ;)

    http://www.coffeeresearch.org/coffee/roasting.htm

    Mal.

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    Re: Time between first and second cracks...

    Thanks Mal,

    That helps a little bit, but doesnt answer about heat ramp levels, rolling cracks etc. The roast I did I managed to keep the first crack rolling for five minutes. I have no idea what this will do for the flavour.

    I think I will have to buy a lot of one type of green bean and shut myself away for a long time. See what happens.
    Will be a shame to waste a lot of green beans though! :(

  13. #13
    Mal Dimal's Avatar
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    Re: Time between first and second cracks...

    Dont know that you will be wasting a lot of beans mate; unless you actually fry them or pull them straight after First Crack or some such thing.

    How about modding a popper to give you more control over the processes? This decreases the batch size considerably (lessening the degree of potential for wastage) and allows you the opportunity to learn a great deal. Thats basically what I did....

    As far as controlling the rate or intensity of First and Second Cracks, you really need to closely monitor the bean mass temperature during these events to have any hope of understanding what is actually going on and then make adjustments and record observations. For what its worth, I try to adjust the heat input at these milestones so as to achieve a smooth transition from the thermal gradient immediately prior to the events, to that during the event (and afterwards too if that is my intention).

    Failure to observe the most opportune time to make these adjustments whilst also allowing for the thermal inertia of the bean mass and the roaster, will not allow you the degree of control that would be otherwise possible. All of this information can then be used (with some modification) from one roasting method to another as the aims still remain the same, i.e. control the roast profile to a predetermined set of gradients while accounting for the various roast progression milestones.

    Anyway, I guess you can see what Im getting at..... If you want to exert full control over your roasting system then you need to be able to accurately measure (and record) all relevant data for post analysis, otherwise, how will you know how to make precise adjustments to your processes and overall decisions on how to manipulate the profiles of specific beans/crops so that you can extract the best possible outcomes for your palate?

    In the end, it really is all down to you and how easily satisfied you are and because we are all using completely different roasting systems (though outwardly similar) there just isnt any blanket set of rules available to help you predetermine an outcome on your particular roasting system that will suit your palate. You really do need to experiment, observe and record.... No easy way out Im afraid :)

    Mal.

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    Re: Time between first and second cracks...

    Quote Originally Posted by Mal link=1213594195/0#12 date=1231407718
    Dont know that you will be wasting a lot of beans mate; unless you actually fry them or pull them straight after First Crack or some such thing.

    As far as controlling the rate or intensity of First and Second Cracks, you really need to closely monitor the bean mass temperature during these events to have any hope of understanding what is actually going on and then make adjustments and record observations. For what its worth, I try to adjust the heat input at these milestones so as to achieve a smooth transition from the thermal gradient immediately prior to the events, to that during the event (and afterwards too if that is my intention).

    Failure to observe the most opportune time to make these adjustments whilst also allowing for the thermal inertia of the bean mass and the roaster, will not allow you the degree of control that would be otherwise possible. All of this information can then be used (with some modification) from one roasting method to another as the aims still remain the same, i.e. control the roast profile to a predetermined set of gradients while accounting for the various roast progression milestones.

    Anyway, I guess you can see what Im getting at..... If you want to exert full control over your roasting system then you need to be able to accurately measure (and record) all relevant data for post analysis, otherwise, how will you know how to make precise adjustments to your processes and overall decisions on how to manipulate the profiles of specific beans/crops so that you can extract the best possible outcomes for your palate?

    In the end, it really is all down to you and how easily satisfied you are and because we are all using completely different roasting systems (though outwardly similar) there just isnt any blanket set of rules available to help you predetermine an outcome on your particular roasting system that will suit your palate. You really do need to experiment, observe and record.... No easy way out Im afraid :)

    Mal.
    Thats what I kinda meant!

    I first learnt to roast with a heat gun and a flour sift. This gave little control and I could only tell what was happening via colour/smoke etc. I would get to FC in 6 mins. SC would come about 7 mins later.
    I dont in any way regret it, I learnt a lot.

    Now I have a highly modded Corretto. Please see http://coffeesnobs.com.au/YaBB.pl?num=1230273327
    Since then I have modded it more!
    I have put more insulation between the controller and the roasting area, put a fan in (I can now do roast after roast after roast) and raised the heat gun a little (I had some tipping, all gone now). I also have made a lid with two holes, one for the heat gun, another for chaff to exit.

    With a short amount of experience (mainly learning the "heating lag") I found I can control the heating ramp anywhere within the roast, the point of FC and SC and the intensity of them. Can you really do that with a popper? I am not asking in arrogance, I have no experience with a popper.
    I have even found a large difference in the cup between using the heat gun exclusively and the heat gun combined with the bread maker element. Too many variables that can be controlled for my little brain. :-/
    I think I went too far in modding the Corretto. I am even think of getting the PID to pulse the heat gun element instead of the whole gun and putting in another thermocouple to see what air temp is. I need to stop!
    Should have kept it simple to start with!

    It seems that I will have to get a large amount of the one type of bean, roast in many different ways all in the same time period (a couple of days) and start cupping them all.

    What I meant by a waste is what willl I do with all the roasted beans? :o
    I only know a couple of people with grinders.

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    Re: Time between first and second cracks...

    What I meant by a waste is what willl I do with all the roasted beans? Shocked
    I only know a couple of people with grinders.
    Hi Bassway,

    I have a grinder and a habit to feed. Just saying, thats all ::)

  16. #16
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    Re: Time between first and second cracks...

    Quote Originally Posted by ACog link=1213594195/0#14 date=1231456954
    What I meant by a waste is what willl I do with all the roasted beans? Shocked
    I only know a couple of people with grinders.
    Hi Bassway,

    I have a grinder and a habit to feed. Just saying, thats all * ::)
    Yea me too and getting low... Damm I am in Brisbane :(

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    Re: Time between first and second cracks...

    Heres some science of roasting info http://www.sweetmarias.com/roast.carlstaub.html
    farm

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    Senior Member Pavoniboy's Avatar
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    Re: Time between first and second cracks...

    My biggest lesson in my first roast was the thermal inertia or heat lag. 1st crack came a little earlier than I expected (but now I know how far out my thermometer is) and thus I didnt start backing off the heat gun until first crack began. I also had no idea of how far to back off being first go.

    What I found was I backed it off - temp still climbing pretty fast, back it off more - temp still climbing fast, back it off more - temp still climbing fast, back it off more - temp starting to slow down, realising I have probably backed it off too much now as my brain is pushing forward my physics knowledge of inertia and how it would apply to heat, second crack began - removed - so backing it off too much not an issue this time.

    My notes for next time are to start backing off the heatgun a bit before 1st crack arrives in the hope of achieving the slowed gradient by the time 1st crack is happening, and to back it off less than I ended up doing last time.

    Following on from the lid with a hole for heatgun and a hole for chaff to escape... I note you are controlling your heatgun temps. Is anyone using this lid method with a heatgun with only two settings? How do you find it? Do you switch back and forth between low and high to control temp or still remain on high and adjust height? I have placed a probe above the beans (as well as in the beans) to monitor air temp above beans and think that starting to play with a lid etc is when this may come in handy.

    thanks,
    Travis.

  19. #19
    Sleep is overrated Thundergod's Avatar
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    Re: Time between first and second cracks...

    I think height adjustment works well.
    Switching heat between Hi and Lo would not do give a stable temperature.

  20. #20
    Mal Dimal's Avatar
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    Re: Time between first and second cracks...

    Behmor Coffee Roaster
    Quote Originally Posted by bassway link=1213594195/0#13 date=1231454031
    With a short amount of experience (mainly learning the "heating lag") I found I can control the heating ramp anywhere within the roast, the point of FC and SC and the intensity of them. Can you really do that with a popper? I am not asking in arrogance, I have no experience with a popper.
    Hi again "bassway"....

    You certainly can, with very simple mods applied or you can go the whole hog and control both the heat output and air flow rate. With my "sample" roaster ::).... I have installed a slightly lower output heating element and upped the fan supply element slightly. All I have to do when roasting (while monitoring bean mass temperature) is to adjust the air flow rate by blocking/opening the exhaust of the popper by varying degrees, which provides an excellent level of control, no matter what the ambient temperature is. If I wanted, it is possible to roast batches of up to 200g at a time with my slightly modded Mistral Popper but since it now performs sample roasting duties; batch sizes are kept between 80-100g.

    Some CSers have completed extensive mods to their poppers, thyristor control of the heating element; complete separation of the fan and heating supplies so that either/both can be controlled independently and at least one person who has installed a PID Controller to manage the heating profile while manually controlling the fan output to control the "fluid bed" activity. Im pretty sure Ive seen some home-roasters over in the States who have gone even much further than this to exact the finest level of control of their roast profiles.
    Not that dissimilar to what youve dome with your Corretto :P ::)... ;)

    Anyway, the main point of all of this is to ensure that you are having fun, while learning something about a whole new process that you havent previously experienced and to top that off.... you get to sit back, relax and enjoy great coffee as a result. Doesnt get better than that..... 8-)

    Mal.



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