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Thread: I dont think I am roasting properly? Temp data included

  1. #1
    Junior Member
    Join Date
    May 2009

    I dont think I am roasting properly? Temp data included

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I am new to the world of roasting. I have roasted 5 batches, but I dont think I have things correct. I would like your help.

    My setup is a popper, with vents on the side. I have inserted a thermocouple in the side today to monitor temps. I have added a tincan to use as a chimney.
    I add 90grams of green beans after waiting 30seconds for the popper to warm up, they spin by themselves.

    I have been stopping my roast after 6 mins from reading people comments, but I cannot tell if I am reaching second crack? today I let the roast go on for 13 mins and recorded the temps and description each 30seconds. Can you tell me when I should have stopped roasting? I am using PNG beans.

    here is my log;
    -0-30 25c turn *on popper and wait 30 seconds.
    0:00 156c. dump 80 grams of green PNG beans.
    0:30 177c. some cooking smells coming from beans
    1:00 186c
    1:30 196c some browning to beans.
    2:00 200c - sounds like first crack startin (a single crack sound)
    2:30 204c - no cracking sounds
    3:00 210c - some crackling sounds plus small amount of smoke
    3:30 213c - more crackling (sounds like the peak of popping sounds, quite active)
    4:00 215c - some more loud crackling
    4:30 218c - cracking seems to have stopped
    5:00 218c - slight crackling
    5:30 220c - a few pop sounds
    6:00 221c - pretty much silent
    6:30 222c - no sounds
    7:00 223c - more silence
    7:30 223c - more silence
    8:00 224c - cracking sounds, but could be the sound of beans tumbling around?
    8:30 222c - sounds pretty quiet in there. bans are a dark brown, but colour looks nice
    9:00 225c - some rattle sounds, could be cracking, but could just be the beans hitting the walls
    9:30 225c - no change
    10:00 227c - divots start being spat out the chimney. in 30 seconds 4 divots have been spat out.
    10:30 226c
    11:00 226c - some more divots spit out, say another 4 or 5.
    11:30 228c
    12:00 227c sounds like 4 or 5 *crackle sounds, 4 or 5 divots pop out
    12:30 227c more cracking and divots - say a total of 15 divots have come out in the last 2 mins.
    STOP and dump beans onto cooler. beans cool within 2 mins.

    I have included three photos. they are of my beans roasted at 6 mins, 9 mins and the ones from this sample at 13mins.

    the 6 min beans brewed from my espresso taste green, a bit like grass or tree leaves
    the 9 min beans taste pretty good
    the 13min beans, I have not tasted, but expect them to taste good, even though they have what I would call divots, or craters. *

    so, what is your interpretation of what is going on?



    Gday coffeecoffee...... [smiley=thumbsup.gif]

    Can you keep image size to a maximum of 640(W)x480(H) pixels please mate? Larger images can slow down page loading considerably, especially for people with limited bandwidth connections..... :(

    If you are unsure about how to easily resize your images,
    this link will hopefully assist :).


  2. #2
    Mal Dimal's Avatar
    Join Date
    Oct 2004
    Warwick, QLD

    Re: I dont think I am roasting properly? Temp data included

    Welcome coffeecoffee.... [smiley=thumbsup.gif]

    From your photos above, that roast doesnt look too bad mate. The roast profile looks pretty reasonable too for a popper. Probably the best thing I could suggest is, that you sacrifice a batch or two of beans and take them right through until they are thoroughly black but not so far that theyre likely to catch fire. That way, you will get a much better idea of what all the milestones are and the various tell-tales that herald the onset of some of these milestones.

    Just be as observant as you can (seem to have that covered pretty well already) and take plenty of notes for future reference. The batch you roasted above, give it a few hours to degas a bit and then start making brews via your favourite method, while making note of the flavour changes that you are able to observe as the batch develops and continues to degas. The changes can be quite significant and important for you as you will then be able to identify when the flavour has developed to the point that you really enjoy. Just note down your impressions along side the batch notes and you are well on your way.

    All the best mate and happy roasting.... :)


  3. #3
    Junior Member
    Join Date
    May 2009

    Re: I dont think I am roasting properly? Temp data included

    Hi Mal,

    I thought I was sacrificing a roast by going to 13 mins.. do you think I havent yet reached SC? can you see the divots in the beens from 13 min photo? is that normal?

    I am going to build a machine based on heatgun and breadmaker, but thats only once I know what I am looking for in my roasting.


    PS: re the image sizes, noted. I can do that.

  4. #4
    Senior Member
    Join Date
    Oct 2008

    Re: I dont think I am roasting properly? Temp data included


    firstly welcome! ;D

    I am also a popper roaster and used to have the same problem as you with the divots coming off the beans around the same time. Now I am no aficionado, but by reducing the temperature of the roast I was able to complete eliminate the divots in the bean. TG has mentioned throughout numerous threads about ways to reduce the temperature in popper roasting. I personally have removed the base plate on my breville crazy popper and replaced it with fly screen, put a chimney on the popper and sit a large fun under the popper during roasting. I now finish around 14 minutes @ ~220degC.

    Let me know if you want any photos or any other help


  5. #5
    Senior Member
    Join Date
    Feb 2009
    North Rothbury, NSW

    Re: I dont think I am roasting properly? Temp data included

    Hi Coffee X 2

    May I ask if your popper is new?

    I started with a popper which had been sitting in the cupboard for a number of years. I didnt get any scorch marks as you had but I was unable to discern second crack. One of my experimental first roasts went to 18 minutes with no joy.

    A bit of investigation led me to sweetmarias, and in there it is explained that a lot of poppers have 2 heat elements so while a popper looks to be doing the right thing, it may not. 1 heat element may have died hence spinning, spinning, spinning...

    Ill have a look and try and find the link for you.

    Then I did a roast and the whole popper went left field, motor up n down etc and I heard second crack well and truly.

    A quick timely trip to a department store and poppers were on for $12.50. Got another one (well, 2, one for popcorn :-?) and we are 6-8 minutes into second crack ever since.

    Only use it for blending experiments but have to say that second crack is really noticeable so I wonder if you have experienced the same problem.

    A mate of mine just starting out had exactly the same problem with a popper that had been sitting in his cupboard too. That is why I thought it worth bringing up.

    Hope this is of help.

    If you include your location in your details there is an army of snobs who will gladly let you do an equipment comparo.


    ...well Ill show you mine...

  6. #6
    Senior Member
    Join Date
    Jan 2008

    Re: I dont think I am roasting properly? Temp data included

    Behmor Coffee Roaster
    Hey James,

    The "divots" are the product of the second crack and are normal. *Your second crack seems to have started at around 225c. *It is usually quieter than the first crack and sometimes shorter in length. You definitely reached second crack in that roast.

    When to pull the roast depends on the type of bean and your own flavour preferences. *Going more than 2 minutes into second crack is too far for many people and results in burnt flavours that destroy the unique flavours of the bean. *That said, some beans like to roll around into the second crack to reach their full potential.

    Many of us pull beans at or around the beginning of the second crack to maximize the unique characteristics of the bean. *Try different roast depths for each bean and see what you like. *

    Good luck. *Have fun and find a bread maker. *


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