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Thread: Questions about Gene

  1. #1
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    Questions about Gene

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi, I just got a gene cafe yesterday!!! woohoo!!!

    and I did two roast yesterday

    Peru Organic Fairtrade 200g (17mins, 229c):
    1st crack at 13mins30sec
    1st crack end at 14mins30sec
    2nd crack didnt happened


    Peru Organic Fairtrade 200g (21mins43sec, 229c):
    1st crack at 13mins30sec
    1st crack end at 14mins50sec
    2nd crack at 19mins40sec
    drop at 21mins43sec


    The result of cracks looks quite similar, but there is one question here

    Is there any different between

    200g, set temperture 229, 17mins &
    200g, set temperture 229, 21mins (but early drop at 17mins)

    What I want to know is does machine accelerate differently?

    And also, if I drop the temperture during roasting process, saying from 230c to 180c, what is it gonna happened inside? the machine stop putting hot air until 180c? or it cool down with "somthing"?

    Daniel

  2. #2
    Senior Member speleomike's Avatar
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    Re: Questions about Gene

    Hi Daniel

    I often drop the temperature at the first sign of 1st crack (FC) so that the time to 2nd crack (SC) is extended. But I dont drop to 180C that would probably be too low as you still want to "roast" the beans in hot air (which allows Maillard reactions to occur). Perhaps drop to 225C.

    As to a difference betwwn run 1 and 2 - wait a week and then try them. Let us know what batch tastes better or what the difference is. I think a drop of 180 might be a bit low but it did extend the roast time so it may well improve the roast.

    I often use 235 C till FC then drop to 228 C and end at SC.

    As to your question if you drop the temp to 180 - the heater will turn off,
    as the heater cools the air blowing past the heater and over your beans will drop in temp, then when the thermocouple at the end of the chamber (just above the exhaust) reads lower than 180C the heater will come on until its above 180 then go off again. The heater will just turn on/off to maintain 180C, the air will always blow until the Gene is < 60 C.

    > What I want to know is does machine accelerate differently?
    I dont know what you mean by that question.

    Mike


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    Re: Questions about Gene

    Hi Daniel and welcome to CS...

    All roasters, be they poppers, dog bowl/heatgun, corretto, Gene or Hottop will vary in the speed at which the temperature climbs (I assume that is what you mean by "accelerate") depending on many factors....

    One (under your control) is the volume of beans....

    The others (little or no control over)...

    There is a little variation in heater power from machine to machine (manufacturing tolerances)
    Ambient temperature - hotter ambient will give a faster increase in temperature
    Air movement near the roaster - outdoors on a windy day will slow the increase
    Mains voltage - lower voltage means a more gradual increase in temperature......

    You have to adjust your technique to compensate for these if you want consistent results. Similarly what will work for one roaster in a given location with a certain set of the above will not work in another location. You need to find what works best for your roaster and how to change the parameters depending on the above "factors"....

    Hope that helps.

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    Re: Questions about Gene

    Temp should increase at same rate until the solenoid starts to click.

    I added a temp guage to my Gene in the hot box directly after the outlet for the machine by drilling a small hole in the hot box lid and sliding a long probe in.

    This should give exactly the same temp as the machine as I understand the machine reads from just after the air exits the main chamber, but the temp seems to be 30 degrees lower (193 in hot box = 227 indicated on gene) and is delayed gong down, where the hot box is 20 degrees warmer than the readout.

    I tried 250 but at 17.5 minutes it resemble charcoal ...

    Currently running at 230/20 minutes gave CS9-10 and 235 for 22 minutes CS 10. Having trouble hearing the crack but I notice lots of chaff suddenly appearing, so assume its then


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    Re: Questions about Gene

    Quote Originally Posted by jaclarkaus link=1227958539/0#3 date=1228007083
    Temp should increase at same rate until the solenoid starts to click.

    Hi jaclarkaus and welcome to CoffeeSnobs


    In an ideal world - that is true!

    However in the real world..... someone turns on a high powered appliance..... mains voltage drops.... rate of heating on the roaster decreases!

    If it was hotter (ambient) when you did your last roast than for this one..... rate of increase will be less! etc... etc...

    The bottom line is - you control the roast..... you watch what is happening (with the aid of any instruments you might have - like a temp probe) and then you make adjustments to follow the same profile......

    If you dont then each roast will be different (not necessarily bad, just different).

    Roasting, with any roaster, is a very manual process if you want the best and /or consistent results.

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    Re: Questions about Gene

    Hi all,

    Thanks for all the tips, so basiclly GC increase temp just like oven, once it reach up to the temperture, it will switch off and on to stay at that point :-?

    Here is my idea, maybe its stupid, but I used to roast with bigger machine before, and we have that air flow control swtich, I noticed GC doesnt have it (most of small roaster doesnt have it), is it "possible" that I can cover up the chaff to let the heat stay inside the drum? or would it break the machine :(

    Lastly, did anyone try to do double roast before (drop the bean after dry process, cool it down and roast again)? how is the result come out?


    Daniel

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    Re: Questions about Gene

    Daniel,

    There is a BIG difference between the larger (professional and semi professional roasters) and the range of domestic machines.

    Changing the airflow through a Gene (especially reducing it) will almost certainly cause premature failure (and certainly void the warranty on the roaster). The temperature inside the drum will rise quite quickly and the element (which relies on air flow to keep the temperature within reasonable limits) will overheat.

    We (Pullman Espresso Accessories) sell both the Gene and the Hottop.... and both will perform very well given correct use.... *but in both cases Id personally (and Pullman Espresso Accessories) would advise very strongly against tampering with the roasters to gain better/different performance.

    Whilst they are both great home roasters, they are not, nor will they ever be capable of the adjustment of say a sample roaster costing many thousands of dollars and only roasting 100 grams.

    If you learn to use these roasters correctly, you will produce excellent quality roast beans.... but modify them (especially restricting air flow)..... and you may well end up with a fire in the roaster!!!!

    I have injured "roastus interruptus" a few times thanks to Western Power! If the roast stops before FC (the earlier the better and stopping at the drying process is quite early).... then re roasting from that point doesnt seem to affect the flavour that much (the resulting roast is acceptable - probably not quite as good as a normal roast) however if interrupted post FC..... I just throw them in the bin! The flavour of the re-roasted beans (to my palate) just isnt acceptable. At that point you are stalling the important chemical changes occurring in the beans..... and this has unfortunate results :P

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    Re: Questions about Gene

    Thank you JavaB! Whatever you said I am totally agree :) And thank you for stop me those weird ideas, hahaha ;D

    next question is....(sorry, just cant stop thinking)

    HOW TO ROAST WET PROCESS HARD BEAN WITH GC :-?

    Daniel

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    Senior Member speleomike's Avatar
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    Re: Questions about Gene

    Hi

    Yeah I know the Gene says on the side "Dry Processed" - just ignore it.
    Perhaps an importer here might know why it says that on the side.
    It roasts wonderfully any wet or dry processed coffees that I have given it.

    Mike

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    Re: Questions about Gene

    My guess is that "Dry Processed" is Taiwanese English!

    What they are trying to say is that the beans must be processed (not just coffee cherries!) with a moisture content in the normal range somewhere about 18%.....

    In other words any beans purchased from a retailer here in Australia (made using either a wet or dry process) are fine - or if grown at home they must have the pulp removed and then dried to the correct moisture level before roasting......

    And as Mike said above, the process used to separate the beans from the "flesh" is immaterial - both roast perfectly.

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    Re: Questions about Gene

    Haha JavaB,

    Yes, I am Taiwanese ;D gez you know lots of things~

    Anyway, if you know what I am talking about, do you know how it should work while "dry processed"

    Daniel

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    Re: Questions about Gene

    I took the dry process and the mark to indicate that for dry processed beans, dont put more than the mark in, but wet processed you could, presumably because they generated less chaff?

    Maybe the dry processed actually means unprocessed like unroasted ...

    Seems like most people stick to 250gm which is below this line anyway

  13. #13
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    Re: Questions about Gene

    Hi Daniel

    As jaclarkaus said just stick to 250 gm or less. I would suggest to weigh out your beans each time as the weight will slightly affect the roasting.

    As a guide I found that 100 grams was too small as by the time I ground in the grinder setting I didnt have enough to actually enjoy. If you use 200 gm of beans thats a nice amount for the Gene for any type of bean. If you use 300 gm it can sometimes get away from you for some beans.

    So for beginning I would suggest to weigh out 200 gms. Use a cheap electronic kitchen scales, they should be around $20 or less. Otherwise did you get the white plastic scoop with your Gene? (Its about 6cm dia, 3cm deep) One scoop is about 100 gms so until you get scales use 2 scoops of green beans per load.

    Mike

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    Re: Questions about Gene

    I tried 500g a week or so ago and that amount of bean blocked the hot air inlet, caused 1% of the beans to get burnt, tanned another 9% and left the remaining 90% green as green. At 250g the beans are getting close to the hot air inlet so I doubt youd be able to go much over that.

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    Re: Questions about Gene

    Behmor Coffee Roaster
    Nice Blend Greg! ;D



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