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  • profile to FC

    I was looking at this link http://www.bootcoffee.com/ROAST3.pdf regarding lighter roasts (1min post FC) and noticed that the profile was convex from 0 - FC rather than concave (if that makes sense). i.e. It starts of slower and the rate increases the closer you move to FC.

    Is this best for lighter roasts only? I remember reading that a quick climb to 150deg (4 or 5 min) was ideal. The roast on the link doesnt get there until some time later.

    Many profiles Ive seen have a steeper climb then slower rate of approach to FC.

    Would anyone care to explain the differences between concave, flat climb, and convex?

    Cheers,

    sd

  • #2
    Re: profile to FC

    Cant explain this for you sorry, hopefully someone will.

    However I was also reading this and thinking my roasts on a corretto are normally a steep gradient at the start and flattening out as I approach 1C so that the gradient is ready for a go slow between 1C and 2C.

    I have just begun to alter this to an ever increasing gradient and then back to a slower gradient between 1C and 2C to see the difference. I have only done one roast attempting this and didnt do too well in following the temp profile I was aiming for...so more attempts on the cards. I havent opened this roast yet, still degassing (but it wont be that useful given it didnt really match the profile I was aiming for).

    I will let you know my thoughts once Ive tasted a few roasts as to whether I am getting any improvement. Note I am usually roasting to the first signs of 2C (slight variation depending on bean), not the light roast that Boots talks of.

    Have you begun trying this type of profile? Let me know what you think if you have.

    Comment


    • #3
      Re: profile to FC

      Gday "sd",

      Ive been using this type of profile now for a number of years, even before I found this info on Willems website but it was another Dutchman who first gave me the idea in the first place, just cant remember his name at the moment. Maybe its something that was originally promulgated within the specialist roasting industry in Holland? I dont know really.

      This style of roasting really suits someone who enjoys all the nuances and complexity of flavours that can be encouraged from high quality beans such as we here at CS are privileged to have access to. Ive never been a fan of really dark roasts and would rarely take a roast into Rolling Second Crack(RSC), most often pulling them after regular Second Crack(SC) snaps are being heard. It was actually Javaphile who encouraged me to try roasting lighter again, before the first few snaps of SC are even heard at all. This is not as straight forward as it sounds as you really do have to pay a lot more attention to the bean mass temperature at all stages of the roast and even though I had already started roasting to an accelerated profile towards FC, I now paid a lot more attention to the temperature around RFC and after RFC had finished.

      In my opinion, this is really worth the effort as it forces you to learn more about the roasting process and appreciate the specific needs of each bean type and so adapt the profile to suit each type. For the most part, my roasting profiles all appear to be very similar at first glance but what is different, is the amount of heat being applied to achieve the desired profile for each bean which may result in slightly shorter or longer ramps up to FC but less variation of the profile after RFC. I dont have any profiles that are less than 4:30 minutes after RFC and none that are longer 6:00 minutes, whether or not SC is being reached.

      I think its worth pursuing this type of roasting profile for most, if not all your beans but you must have a means of measuring the bean mass temperature otherwise just doing it by colour or time alone, for example, will not produce as consistently repeatable results. Its great fun though and really makes the whole roasting process a hell of a lot more interesting and the bonus of great coffee in the cup more often than not. Gotta love that.....

      Mal.

      Comment


      • #4
        Re: profile to FC

        thanks mal. i was hoping youd respond to this one. ill definitely give it a go. i have a little Waghi left that deserves a lighter roast...and I hear theres more coming anyway.

        Comment


        • #5
          Re: profile to FC

          Interesting to find this thread again... I went along to St Ali on a visit to Melbourne last week and was lucky enough (and nosy enough) to be invited behind the counter to watch the end of one roast and the entire next one. A real eye-opener!

          From the looks of it, they were using a similar profile (for the bean I saw them roasting - an Indonesian). I dont want to spill any secrets here, but the guys explained that they consider the first 3 minutes of the roast as the "soak" stage, where the beans are gently warming up (and drying out, Id add). They then ramp things up to FC and down again once its established.

          There wasnt a whole lot of adjusting the temp during the ramp to FC tho, so Im not sure if the profile would really fit the curve you were describing, SD, or whether it was just a gentle start with a straight ramp thereafter. Obviously, the bean temp MIGHT look concave even if the roaster temp is unchanged until FC... who knows.


          Anyway, Im interested in this "soak" business... Is it something specific to drum roasters (though I cant think how it could be...)? Or is it the same as the "drying out" stage Ive heard others talk about - though Ive never tried it. What does it achieve and is it recommended/necessary only for certain bean types/profile types?

          Also, Im beginning to wonder about something. We all talk about ideally reaching FC around 10 minutes or whatever, but given that any kind of soak/drying stage of the roast is likely to take place at temps below where anything significant is happening within the bean, isnt it more important how long the bean take to get from, say, 50C to FC? ie. if a roaster is employing a 3, 4 or even 5 minute soak to ~50C, then reaching FC 9 minutes later, describing this as a 14 minute ramp to FC is not really accurate - since the majority of the "roasting" is happening in a 9 minute timeframe. Maybe this kind of terminology would be useful for people comparing profiles?

          Cheers
          Stuart.

          Comment


          • #6
            Re: profile to FC

            Gday Stuart...

            Well, in my case, I usually get the beans up to 100-120C before accelerating towards FC and this probably takes 3-4 minutes to achieve. As far as the profile to FC is concerned, my experience has been that this stage of the roast, more than any other, can determine the predominance of brighter flavours that are perceived in the cup. Mostly, I keep the ramp from the end of FC towards SC at around the same gradient, regardless. By varying the time and gradient curve towards FC though, you can influence a lot of factors that seem to change the high notes of a beans final flavour profile in the cup.

            Do a bit of experimenting yourself Stuart, with small batches to start with, and Im sure you will be amazed at the differences you can create. Theres much more to roasting than just the time taken to reach FC and then SC (if you go that far) and a lot of control in that first ramp, after the initial soak, seems to have the most influence on the final outcome, that Ive experienced over time... 8-)

            Mal.

            Comment


            • #7
              Re: profile to FC

              Interesting stuff, although perhaps Im a little confused!  :-?

              OK…I’ve reviewed my roast profile(s) up to FC for the last half a dozen roasts with my Corretto set up. Typically the height of the heat gun isn’t adjusted from the beginning of the roast to FC, which normally occurs between 203>205 degrees somewhere around the 11.5>12.5 minute mark.

              What I have noticed is that temperature climbs VERY steeply in the first 3 minutes (28 – 32 degree increase in temp. at end of minute one, 27-31 degree increase at end of minute two, and 19-26 degree increase at the end of minute three). At this stage temperature in the bean mass is around 107-114 degrees (temp at start of roast usually high 20’s).

              Temperature then increases less dramatically (17-20 degree increase at the end of minute four, 14-17 at end of minute five, 11-13 at end of minute six, 10-12 at end of minute seven, 7-10 at end of minute eight). After that anywhere from 6-9 degree increase each minute until FC.

              I assume this “soaking” and other parts of the strategy discussed above suggests reversing this naturally occurring steep climb followed by the flattening out. If so, keeping the heat gun quite high at the start of the roast, then dropping it down quite substantially perhaps a few times after approx. 120 degrees to start bumping up temperature? Correct?

              Comment


              • #8
                Re: profile to FC

                The way I do it on my corretto is starting the gun high above the bean mass on low heat up to around 60 degrees, crank it up to high heat until around 100 degrees and then start lowering the gun to continue cranking up the gradient, and then backing off into FC through to SC if going that far.

                So, yes Buschy what you describe sounds right to me.

                Comment


                • #9
                  Re: profile to FC

                  I had a go with the "soaking" this morning.   My heat gun isnt variable speed so I have to raise and lower to adjust temp. It took 6 minutes to get from 25 to 100 degrees, then I had to lower the gun as far as it would go in order to reach FC 6.5 minutes later at 203. I was a bit worried but the roast looks even and ended up being CS9. I pulled it just before SC at 17.5 minutes. It will be interesting to see what beans taste like in about 6 or 7 days.  :-/

                  Its strange...even though the heat gun was quite high at first and then very low, the temperature increase was more even from minute to minute up until FC than before.

                  Comment


                  • #10
                    Re: profile to FC

                    let us know how it goes...



                    Comment


                    • #11
                      Re: profile to FC

                      Originally posted by 072A2E222F430 link=1233884536/5#5 date=1240819341
                      Gday Stuart...

                      Well, in my case, I usually get the beans up to 100-120C before accelerating towards FC and this probably takes 3-4 minutes to achieve. As far as the profile to FC is concerned, my experience has been that this stage of the roast, more than any other, can determine the predominance of brighter flavours that are perceived in the cup. Mostly, I keep the ramp from the end of FC towards SC at around the same gradient, regardless. By varying the time and gradient curve towards FC though, you can influence a lot of factors that seem to change the high notes of a beans final flavour profile in the cup.

                      Do a bit of experimenting yourself Stuart, with small batches to start with, and Im sure you will be amazed at the differences you can create. Theres much more to roasting than just the time taken to reach FC and then SC (if you go that far) and a lot of control in that first ramp, after the initial soak, seems to have the most influence on the final outcome, that Ive experienced over time... 8-)

                      Mal.
                      Hi Mal

                      Thought that what happens below 150C was just about getting the right level of moisture in the beans before proceeding into the roast - does it make any difference sub 100C? What effect do you see changing the very low end profile?  I just get up to 110C as fast as possible (usually < 60 secs) then launch my profile... this is the best summary explanation of the roast process that i have come across from Jim Schulman @ H-B (see below). These coffee beans are very complex reaction vessels!

                      Eric

                      There are three basic things happening when you roast coffee: 1) water
                      evaporates, 2) organic acids and aromatics break down or are boiled off, and
                      3) water, sugars, and amino acids combine in a chain of chemical reactions
                      collectively called the Maillard reaction.

                      * Water Evaporating: This happens from the moment the beans are heated up
                      * to the first crack, when the remaining free water escapes. As the beans
                      * exceed 300F, a steam wave moves out of the bean from its center. This
                      * wave also starts the Maillard reactions (see below). Below 300F bean
                      * temperature, not much is happening except water evaporating. If the bean
                      * is too moist going above this, the bitter organic acids will not break
                      * down as quickly (see next section). If too much water evaporates, the
                      * Maillard reactions are starved, and the roast will be dominated by dry
                      * distillates. The drop-in temperatures or early bean heating should be
                      * adjusted to achieve this balance

                      * Organic Acids and Aromatics Breaking Down or Boiling Off: Roasts have to
                      * go to partway into the first crack, since this is where the chlorogenic
                      * acids that make unroasted coffee intensely bitter finish their
                      * breakdown. The smaller acid molecules and aromatics, which are
                      * responsible for the fruity aromas and acidic tastes start breaking down
                      * around around here. The longer the beans stay at temperatures above
                      * about 390F, the lower the acidity of the result. For instance, it is
                      * said that Italian espresso roasters stall the beans around the first
                      * crack to reduce acidity without reaching temperatures that caramelize
                      * off the sugars. Too much of this is a roasting flaw called baking, which
                      * overly flattens the flavor of the coffee.

                      * Maillard Reaction Chains: This is where the complexity of coffee is
                      * created, since these reaction chains are hugely complicated. However,
                      * there are some overall guidelines. The early Maillard reaction, from
                      * 300F to the 1st crack, creates nutty, toasty, and woody flavors. At
                      * higher temperatures, sugars stop reacting with amino acids and start
                      * caramelizing on their own, creating caramel, vanilla and chocolate
                      * flavors. Finally, also at higher temperatures, and when the water
                      * required for early Maillard reactions and caramelization runs low, the
                      * Strecker degradation changes the compounds created earlier in the roast
                      * to dry distillates: smoky, spicy and peaty flavors. The simplest lesson
                      * here is that these processes compete for water, so that taking longer in
                      * the ramp to the first will and less time thereafter will favor the
                      * woody, toasty, nutty flavors and reduce the caramel ones. Also, if the
                      * roast is to get very dark, the only way to avoid overwhelming distillate
                      * flavors is to dry the beans less (go as fast as possible earlier in the
                      * roast), so the Strecker degradation creating these flavors is
                      * controlled.

                      There is also the inconvenient fact that beans are 3 dimensional objects.
                      Roasts faster than about 6 minutes will have significant differences between
                      the inside and outside of the bean, and the inside can be under roasted;
                      slower roasts will be more even. However, the slower a roast, the more the
                      aromatics are cooked off.

                      So, after making sure one has dried the bean to the right degree in the roast
                      below 300F, and balanced the flavor developments that takes place below and
                      above 400F, one should roast as fast as possible.

                      Comment


                      • #12
                        Re: profile to FC

                        Gday Ce..

                        I basically try to stick to an ever accelerating temperature gradient towards First Crack(FC) that follows a simple exponential curve. Its just something that I found works rather well with the Corretto (mine anyway) after reading some very interesting practical data on coffee roasting by a Dutch chap some time ago. It was never really practical for me to do this with my simply modded poppers early on, but it is easy to manage with the Corretto and produces very consistent end results.

                        So long as I do my bit, the batches are all very evenly roasted throughout the batch and intra-bean too. End results in the cup are also very consistent and depending on the bean, nearly always have lots of character in the flavour profile, especially high and mid notes which is something I enjoy in a cuppa. Too many commercial coffees have plenty of bass notes (not our sponsors though, the ones Ive tried anyway 8-)) but not enough of the intrinsic flavours that often give the bean its particular character.

                        From the few (meagre) experiments Ive done, pushing the beans too hard early on can sometimes accentuate off flavours at the expense of good ones; result in unevenly roasted batches (by external colour) and unevenly roasted beans through the cross-section of individual beans in the batch... Its probably these that cause some of the off flavours Im referring to. Perhaps some of the techno-babble in Jim Schulmans treatise quoted by you, goes some way to explaining these processes scientifically. When its all said and done, I just test my efforts by the quality in the cup and if somethings not quite right, not as good as earlier crops of the bean for example, I head back to the drawing table and modify the gradient slightly, one way or the other, until Im getting the best out of the bean that I can.

                        That part of the roasting curve after FC, I keep more or less constant at a straight line gradient of between 3-4 C/Minute and stop the roast at some point along this line and usually before Second Crack(SC) starts for most bean varieties. It is really important to control the roast during FC so that it doesnt either run away or start to stall; you need to hold a very shallow gradient here until FC starts to taper off and then increase to one something like the gradient above, towards SC. Ive gotten so used to roasting this way now that it has almost become automatic for me but always enjoyable. I think you just need to find something that works for you, with the roasting hardware you use and then make little tweaks as time goes on and you become more confident with the process and... The results in the cup 8-)

                        Cheers,
                        Mal.

                        Comment


                        • #13
                          Re: profile to FC

                          Originally posted by 032E2A262B470 link=1233884536/11#11 date=1241449940
                          Too many commercial coffees have plenty of bass notes (not our sponsors though, the ones Ive tried anyway 8-)) but not enough of the intrinsic flavours that often give the bean its particular character.
                          AND WHAT IS WRONG WITH BASS NOTES? ;D ;D

                          Sorry I just had to go there!

                          As pointed out by Mal, each roaster to their own. What happens in a popper is different to a corretto, your corretto is different to mine, which is different to a 2kg commercial drum roaster, which is different to 20kg roaster, on and on.

                          And how would a home roaster ensure the correct amount of dehydration? Put your corretto on a scale and log not just time verse temp but verses weight as well?

                          Does this apply to all beans?
                          Some of my beans tasted dramatically different with a different roast profile. Even to how and what type of heat was applied. Some others made little or no difference.

                          I did do a couple of roasts on Sunday were I did a slow long ramp to about 150, then quick to FC and another batch were I did a linear ramp to FC. Havent tasted them yet.
                          One thing I did notice was slow ramp was darker inside the bean. The "skin" was lighter. The linear roast was the same colour through the bean. The second half of the roast (FC-SC) was the same, stopping 15 seconds after SC.

                          In my very small amount of roasting experience I have gravitated to a roast profile that seems very similar to Mals. This seems to suit my tastes. This, to me, is the benefit of home roasting.
                          I get what I want!

                          Comment


                          • #14
                            Re: profile to FC

                            Absolutely bassway... [smiley=thumbsup.gif]

                            By the way, can never have too much clean, crisp bass in music; prefer the Double Bass but there are definitely some good electric ones out there with people who know how to use them... 8-)

                            Back on topic now.... :
                            I guess thats what I always try to encourage really, that everyone needs to experiment with their own particular setup and arrive at a profile for each bean type that really sets their palate buzzing. I never mind helping by describing some of the profiles I use myself, to help others get started but in the end, you need to roast to suit your own palate. Not mine or anyone elses for that matter....

                            Just be methodical about your approach, keep good records (including your own cupping notes/impressions) and dont be afraid to try something different now and again (use smaller batches if youre not confident about the outcome). Certainly, read what master roasters like Boot have to say about the way they like to go about things; these people have forgotten more about roasting than most of us will ever learn about it. Sure, youre going to waste some beans learning, along the way but its all part of the process. Roasting is a very tactile and sensory experience and as a result, it is very difficult to convey this in words alone(well, for me anyway). You just need to do it for yourself and learn from your mistakes...

                            Cheers,
                            Mal.

                            Comment


                            • #15
                              Re: profile to FC

                              Thats what I love so much about home roasting, getting the best out of my equipment and the beans that I am roasting, luckily I have more successes than failures and the family and friends keep lining up for more.
                              Heading out the roastery now to do a batch of Ethiopian Yirgachef

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