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  • Gene Cafe - Preliminary Conclusions (Confusions?)

    Hi All,

    There has been so much keeping me busy in coffee that I have never really tried home roasting seriously. Using the standard profile on the sample roaster at work has kept me more than happy. However, when Dennis decided to ditch one of his Gene Cafes for a sum that I happened to have spare, I decided to give it a bit of a go.

    I had a rather remarkable hiccup that was solved with the aid of a hot scalpel and Im now about ten roasts in. I have decided to try to walk before I can run, so all my roasts so far have been experimental throw-away roasts. I havent seriously mucked around with espresso yet - just a bit of triangle cupping. I am cooling externally with the aid of a desk fan, bucket and sieve.


    Conclusion/Confusion The First: Electrical supply probably makes a difference.


    The gene seems to be performing differently for me than it was for Dennis. Dennis noted that the Gene never reached the setpoint for him. The very same Gene will hit a reasonable setpoint with a full load of beans in just over ten minutes.

    Overseas forums are full of reports of people buying expensive "variacs" to ensure the delivery of a repeatable voltage to their roaster, so I think that it is perfectly plausible that genes that perform the same in the factory perform differently for different forum users. This might explain why many people report that their genes function differently to what people post and adds another reason to the list of reasons why you should view anything that I have to say about roasting with extreme caution! ;P (The same would go for anything that anyone else has to say about genes.)

    With that caveat out of the way, Ill try to continue my list of confusions and conclusions after further triangle cupping, so as not to make a total fool of myself!

    I look forward to input from more experienced home roasters than I am!

    Cheers,

    Luca


  • #2
    Re: Gene Cafe - Preliminary Conclusions (Confusion

    In this thread

     http://coffeesnobs.com.au/YaBB.pl?num=1180502413

    there are reports of time taken for an empty Gene to reach 250C.

    Mostly 8 to 12 minutes.

    Ours takes about 5 minutes (consistently, measured several times). It is
    a recent purchase and has later firmware than probably all those in that thread.
    It may be that, or it may be just voltage variation (242V here pretty much all the time).

    Perhaps you can compare your reading with what Dennis got, if he measured that one?

    (Must update that other thread ...)

    Comment


    • #3
      Re: Gene Cafe - Preliminary Conclusions (Confusion

      Yep, I did...

      ambient temp = 21*, exactly 10mins to 250*

      Remember though...the gene was empty at the time.

      Comment


      • #4
        Re: Gene Cafe - Preliminary Conclusions (Confusion

        Greg and I also completed a Roast off between the Gene and my HT last Monday whilst Greg was in Perth.....

        Greg is just writing up the results so shortly......

        Comment


        • #5
          Re: Gene Cafe - Preliminary Conclusions (Confusion

          Im getting remarkably consistent results with mine by doing a manual pre-heat of 180C, then roasting @ 230C - then stopping the roast at first sign of second crack

          Some users have commented on the relatively slow cool down period, but I have no problems with this (initial trail and error aside) - as by stopping the roast at first sign of second crack, in conjunction with reasonable colour change, what I am noticing is that established second crack kicks in after about 2 mins into the cool down period, producing a very even roast which seems to be at its best 8 to 10 days later

          And by keeping comprehensive roasting notes Im able to repeat these results with the same beans through a relatively hassle free set and forget approach

          As mentioned elsewhere I find upping the recommended roast quantity marginally seems to have a beneficial effect on temperature stability - though of course this varies markedly depending on green bean quality

          Some Cuban beans which I roasted recently were quite patchy compared to others post-roast, and the flavour profile would not be to everyones liking, but I still managed to produce a rich red crema, and the first draw is like that of an excellent Cohiba Robusta - so much so that Ive often thought since about investing in same, and a 61 Delord Armagnac...

          Comment


          • #6
            Re: Gene Cafe - Preliminary Conclusions (Confusion

            Hi all

            Just as an aside NSW will be changing from 240 to to 230 Volts in the next year.
            "In 1983 Standards Australia adopted a 20 year plan to convert Australia from the nominal 240 volts to 230 volts, to align with European Standards – IEC38. The aim was to align Australian manufactured products with our main trading partners."
            Ref. http://www.ieee.org/

            That will have a small impact on our Genes.

            Mike

            Comment


            • #7
              Re: Gene Cafe - Preliminary Conclusions (Confusion

              Originally posted by hazbean link=1203248184/0#1 date=1203249315
              In this thread

              http://coffeesnobs.com.au/YaBB.pl?num=1180502413

              there are reports of time taken for an empty Gene to reach 250C.

              Mostly 8 to 12 minutes.

              Ours takes about 5 minutes (consistently, measured several times). It is
              a recent purchase and has later firmware than probably all those in that thread.
              It may be that, or it may be just voltage variation (242V here pretty much all the time).

              Perhaps you can compare your reading with what Dennis got, if he measured that one?

              (Must update that other thread ...)
              OK, some more data points - ambient 35C, time to get to 250C from "cold" 4min 55sec. The thermocouple on the gene showed 35C at the start, so did my DMM+thermocouple. I think the genes temperature readout is accurate. FWIW: mains voltage (true RMS) 238.6V.

              I cant see how a small variation in mains volts could account for 100% variation! Its got to be a design feature.. (The gene has a LOUD relay that switches the heater on/off - I dont think there is any form of constant current regulation - it is switched over the mains, Id guess).

              /Kevin

              Comment


              • #8
                Re: Gene Cafe - Preliminary Conclusions (Confusion

                Hi all

                The Gene variations are probably just the variation in the resistance of the nichrome wire for the heater i.e. the glowing red thing you see during roasting. The heating rate just depends on the power from this wire heater. This power = I^2R or V^2/R V=Voltage I=Current
                Hence for the same voltage a Gene with a lower resistance wire (e.g. shorter or thicker) will be using more power.

                Mike

                Comment


                • #9
                  Re: Gene Cafe - Preliminary Conclusions (Confusion

                  Originally posted by speleomike link=1203248184/0#5 date=1203288884
                  Hi all

                  Just as an aside NSW will be changing from 240 to to 230 Volts in the next year.
                  "In 1983 Standards Australia adopted a 20 year plan to convert Australia from the nominal 240 volts to 230 volts, to align with European Standards – IEC38. The aim was to align Australian manufactured products with our main trading partners."
                  Ref. http://www.ieee.org/

                  That will have a small impact on our Genes.

                  Mike
                  I think the new standard is +10%/-6% (the existing 240V standard is +/-6%). If you go 230V+10% you get what we have now (well, 253V max instead of 254V). As far as I know, there arent any actual plans to change anything except the labels...

                  /Kevin

                  Comment


                  • #10
                    Re: Gene Cafe - Preliminary Conclusions (Confusion

                    Im getting remarkable repeatable results by using the method I outlined above - today I managed to set and forget a batch for the first time based upon reproducing the same roasting profile for the same beans: 14.5min @ 230C with a 180C preheat for some Cuban Altura Lavado beans

                    Which means that I didnt exactly walk away and not watch the roast entirely, but I did reproduce the same settings as my previous roast and was satisfied with the end result - I also note that th Cuban beans are drinking much better 12 days post roast than at any time previously, brining out a lovely plum liquor flavour on a fleshy mid palate...

                    EDIT NOTE: looking back over my notes I found that my original roast went for 15.5min whereas my second one only went for 14.5min - which is a considerable difference! It has been bloody hot today in Melbourne though, and Im sure that this effects the roasting process, and i certainly observed the puff of smoke that is often associated with the onset of second crack, and even though the roast terminated at 14.5min as preset, second crack was certainly starting to become established at this time, but kicked in good and proper during the cool-down period

                    Guess I have to wait and taste the end result to see if it stacks up the same!

                    Comment


                    • #11
                      Re: Gene Cafe - Preliminary Conclusions (Confusion

                      Originally posted by hazbean link=1203248184/0#1 date=1203249315
                      In this thread

                      http://coffeesnobs.com.au/YaBB.pl?num=1180502413

                      there are reports of time taken for an empty Gene to reach 250C.

                      Mostly 8 to 12 minutes.

                      Ours takes about 5 minutes (consistently, measured several times). It is
                      a recent purchase and has later firmware than probably all those in that thread.
                      It may be that, or it may be just voltage variation (242V here pretty much all the time).

                      Perhaps you can compare your reading with what Dennis got, if he measured that one?

                      (Must update that other thread ...)
                      Thanks for that link; if I had known about it, I wouldnt have wasted everybodys time with my first post in this thread! Apparently the new firmware is better, so I wouldnt worry about it.

                      Yep, I did...

                      ambient temp = 21*, exactly 10mins to 250*

                      Remember though...the gene was empty at the time.
                      Just did it. Not sure what the ambient temp was, but it was relatively cold. It took 6 min 40 to get to 250 when empty. Thats a nice little piece of data for everyone, presuming that the 10 min time was for the gene that you sold me as opposed to the other gene that you had!

                      Cheers,

                      Luca

                      Comment


                      • #12
                        Re: Gene Cafe - Preliminary Conclusions (Confusion

                        Hey guys.. 7 mins for my gene to reach 250.

                        I was wondering whether any of you Melbournites who use the Gene were interested in getting together for an informal roast and discussion of techniques and ideas.

                        Im interested in becoming a better home roaster and perhaps we could all contribute to some ideas and a report on the CS board?

                        Comment


                        • #13
                          Re: Gene Cafe - Preliminary Conclusions (Confusion

                          Originally posted by jazzy_boy link=1203248184/0#11 date=1203648473
                          Hey guys.. 7 mins for my gene to reach 250.

                          I was wondering whether any of you Melbournites who use the Gene were interested in getting together for an informal roast and discussion of techniques and ideas.

                          Im interested in becoming a better home roaster and perhaps we could all contribute to some ideas and a report on the CS board?
                          Sounds like a good idea. Im doing my contribution of ideas in this thread; youre all welcome to join me!

                          The most useful thing to do would be to actually exchange some roasts with other people - preferably of the same bean. I put that idea up as a general suggestion a while ago and got practically zilcho as a response, which struck me as utterly ludicrous for a site devoted to home roasting with thousands of members, most of whom have the same beans!

                          A good way to kick it off might be to spend a few hours pulling shots with a variety of roasts of the same bean at a different profile, or just to do some triangle cupping. Speaking of which:

                          Conclusion/Confusion The Second: The gene is awesome at drying your beans out ... probably too awesome

                          There seem to be many schools of thought out there as to how to use the gene. Because of differences in firmware and voltage, as already discussed, my experiences might be nowhere near close to yours. This thread might well have limited utility - hence the title. I wont make that point again, but it applies to everything that I write here.

                          I also wont again note that I am cooling everything externally.

                          I roasted 250gm batches of a rather good colombian supremo with three different roast profiles:

                          1: Preheat and insert with the temperature reading at 100 when the roast started; set to 230C and dump at second crack

                          2: No preheat, set to 230C and dump at second crack

                          3: No preheat, set to 235C, wait until first crack finishes then drop to 225C and dump at second crack

                          These batches were each drip brewed at 60g/L and I triangle cupped them blind with two other people. We thought that we would have difficulty picking out the differences, given that they were all the same origin, but, to our surprise, the pro roaster, myself and the self-confessed newbie all selected the odd cup out on each occasion. In the first cupping, roast 2 defeated roast 1 (general concensus was that it was much less dull). In the second cupping, roast 3 defeated roast 2 (sweeter, more character).

                          When the beans were cracked open, 1 had a very dark centre, whereas 2 and 3 were a lot more uniform in colour throughout. I really ought to have taken some colorette readings, but the colorette was in the roastery, which was locked up. So thats my excuse!

                          The conclusions that I am working on at the moment are that my gene is really good at getting heat right into the centre of the beans and drying them out. Because of this, I am no longer preheating and I am dropping the temperature off after 1st. I will try the first espresso roast of the colombian supremo from this method this weekend.

                          I think that I will try to repeat this experiment just to be sure that we didnt get any of the samples mixed up or over-roast one of the samples or anything. I also have a number of other things to experiment with - effect of load, temperature drops after 1st of various sizes, etc.

                          Theres a lot of work ahead and, frankly, its all a bit mindboggling!

                          As always, comments, criticisms, questions, etc, are always welcome. But please bear in mind that Im a total newbie to the gene.

                          Cheers,

                          Luca

                          Comment


                          • #14
                            Re: Gene Cafe - Preliminary Conclusions (Confusion

                            Hey Luca - Id love to have a roast off of the same beans I think it sounds like a great idea - I for one feel that Im getting great consistent results from my Gene Cafe, just so long as I keep my eye on the ball and maintain the same parameters - as Ive said previously I pull the roast at the first signs of second crack and go into established SC about 2 to 3 min into the cooling down period - and it seems to work fine every time. Ive also noticed an improvement in the pour quality and over-all colouration by leaving the beans out overnight and then bagging them the following day. Im also finding that most of my roasts are drinking at their best 8 to 10 days, and sometimes later in the case of the Cuban, post-roast.

                            Cheers,

                            Pat

                            PS - If you want you can swing by the caf and pick up some beans that Ive roasted to have a look and to see what you think - just let me know if youre interested so I can bring some in

                            Comment


                            • #15
                              Re: Gene Cafe - Preliminary Conclusions (Confusion

                              hi all
                              i have just bought a new gene cafe and live in the uk so i will checkout how quick the temp reaching on mine with a 240v
                              will keep you posted

                              Comment

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