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Thread: caffeine -- how do they test?

  1. #1
    CoffeeSnobs Owner Andy's Avatar
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    caffeine -- how do they test?


    while we all read about the caffeine content in drinks (obviously coffee included) can any one tell me how they test the quantity? I assume makers of caffeine / sugar drinks know the contant because they add it in.

    It seems that most coffee caffeine content quotes can be sourced to a paper from the 70s (from a time and country that considered simmering for hours good coffee).

    I would love to have a pile of espresso shots tested from different roast depths and origins to get an idea of actual caffeine content.

    So... where do we book a day of caffeine tests?

  2. #2
    Senior Member askthecoffeeguy's Avatar
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    Re: caffeine -- how do they test?

    Try your local doctor

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    CoffeeSnobs Owner Andy's Avatar
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    Re: caffeine -- how do they test?

    seriously?

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    Senior Member Dennis's Avatar
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    Re: caffeine -- how do they test?

    csiro?

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    Re: caffeine -- how do they test?

    Hmmm....sounds like a food lab coming along....All chemicals should be easily available.....but you never know these days buying them could put you on the terrorists watchlist!!

    Here is a simple method.....

    http://www.newton.dep.anl.gov/askasci/chem00/chem00291.htm

  6. #6
    mwatt
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    Re: caffeine -- how do they test?

    http://www3.interscience.wiley.com/cgi-bin/fulltext/68000104/PDFSTART

    Sponsored by illy.

    Scientific description of coffee:

    "Espresso coffee is served in a small, heavy china cup
    with a capacity of 3050ml, half-full with a dark brew
    topped by a thick, clean, light reddish-brown foam of
    tiny bubbles. The liquid part of the espresso is a very
    complex matrix. It is in fact a concentrated solution of
    salts, acids, sugars, caffeine and many other complex
    substances, forming the matrix wherein three dispersed
    phases coexist (emulsion, suspension and gas
    bubbles)".

    The bottom line:



    Sorry about the lack of cropping employed there. But basically 40mg caffeine per espresso shot.

  7. #7
    CoffeeSnobs Owner Andy's Avatar
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    Re: caffeine -- how do they test?

    Cool link NakedBean, ta.
    It looks fairly straight forward and I agree with avoiding benzene (and would add to be cafeful with Lead Acetate!)

    Thanks Michelle, yes some of the figures quoted are fairly current but without knowing the roast depth and origin of the beans (just a generic variety or Arabica / Robusta is often used) I cannot be sure we are real comparing apples.




  8. #8
    mwatt
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    Re: caffeine -- how do they test?

    Hmm, but as I understand it, the paper was also about a method theyve developed to measure caffeine:

    "a potentio-metric enzyme sensor can be used successfully for the direct detection of caffeine in coffee beverage samples. The system described here does not require any sophisticated equipment, being based on a pH meter with a glass membrane electrode".

    So, if that means more to someone else than it does to me, then theyd also be able to analyse and compare espresso beverages made of different origins/ roast profiles.

    My husband was also mumbling something about gas chromatography when I was talking to him about this...




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    Re: caffeine -- how do they test?

    this may be a bit off the wall but what about contacting choice magazine or today tonight and ask if they can recommend a lab they use for food testing, might be a way to also see what methods are used? the csiro would most probably have the facilities to test or a local university but getting the beans to the lab and at what cost would probably come into the equation.
    worth a shot isnt it? (no pun intended)

  10. #10
    CoffeeSnobs Owner Andy's Avatar
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    Re: caffeine -- how do they test?

    Whoops, sorry Michelle, I didnt see the link in the top of your post (eyes just missed it!) and I was refering to the image.

    potentio-metric enzyme sensor eh? I had a bit of scrounge in the shed and dont seem to have one (or a gas chromatograph) ;)

    Normally, high-performance liquid chromatography separation48 and UV spectrophotometric detection 9,10 methods are applied to both regular and decaffeinated green and roasted coffees for caffeine content determinations. Also, other methods such as capillary electrophoresis,1114 thin layer chromatography
    15 and gas chromatography,16 are used for separation of caffeine in the analysis of mixtures, combined with several other detection methods such as mass spectroscopy16 and FTIR spectrophotometric measurements.1719 However, very costly instrumentation, highly skilled technicians and complicated and time-consuming procedures are required for such methods.


    Its a great article (belated thanks) and goes some way to explain why everyone quotes and re-quotes the same old figures... its darn hard to get a good reading easily.

    Sullo, I worked for the local Uni for 8+ years and that might be worth a try. I currently do some work for a business that has a "lab" that test olive oil so I might brush-up on my spanish and have a chat to thier head scientist.

    I did see some reference to a canadian doctor who was developing a simple test but I expect his is a "yes/no" type test.


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    Re: caffeine -- how do they test?

    Hi Andy,

    Not sure how useful this will be, youve probably already covered the ground... *If you do a Google search on "extraction of caffeine from tea" or "isolation of caffeine from tea", you should come across a heap of laboratory prac. procedures for extracting caffeine from tea which should be easily modified for coffee. *Most of the chemicals are relatively safe and should be obtainable, though you will most likely require a fume cupboard, or a very well ventilated open area. *I think the first step of obtaining natural caffeine should not be too hard, purifying it (via crystallisation) might be a bit trickier. *But if you are just after a comparative indicator it should not be too difficult...

    I actually did something similar in my younger days, we extracted caffeine from both Tea and Coffee to see which contained the most. *Interestingly, if I recall correctly, by weight (not cup) Tea actually had it over Coffee. *I cant recall what type of coffee we used (i.e. instant or ground).

    Ive forgotten way too much about organic and analytical chemistry, so cant offer too much more, just wish Id kept my old prac. book.........

    Depending on what you want to do, it might be easier to send of samples to a lab for processing ~ High Pressure Liquid Chromatography certainly looks like the simplest method to use.

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    Re: caffeine -- how do they test?

    You dont really state what degree of accuracy youre looking for but considering Chromo and AAS are out of the question for cost etc, so to would be any chemistry based analytical approach.
    2 quick and dirty things spring to mind that may get you to close enough...

    1. A few standard solutions made from distilled water and pure caffeine (you must be able to buy it somewhere) and a pH reading of those. Then compare or extrapolate from your sample to those standard solutions.......

    2. A quick and dirty "simply boil the hell" out of your weighed samples and then wash and dry and weigh the samples again.......but that will take out all soluble compounds and I dont have any idea what those would be as a % of the caffeine. Of course there would always be some residual caffeine left just as per the water process for de-caff.

    3. Another could simply be extract a normal espresso shot and drop the caffeine out by precipitation.....

    But Im only guessing but it might be some food for thought.....I havent done any chemistry for 20 odd years and all of that was for mineral exploration.


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    Re: caffeine -- how do they test?

    Some more digging,,,,

    Does dark roast coffee have less caffeine than light roast?
    http://coffeefaq.com/site/node/15

    How do I measure caffeine content at home?
    Submitted by Daniel on Mon, 2006-01-16 01:17.
    To the best of my knowledge this can not be accomplished without sophisticated equipment. The Department of Energys web page briefly explains what is involved.

    http://www.newton.dep.anl.gov/askasci/chem00/chem00291.htm

    (I think that is the original URL I posted previously)

    When isolated and purified, caffeine is a white, crystalline powder. It is composed of long hexagonal prisms. It ultimately melts at 458.2 F (236.8C), losing water at 176F (80C) and subliming at 352.4F (178C). It is odorless and has a bitter taste. It is slightly soluble in water and alcohol and is typically heated when incorporated into beverages. Aqueous solutions of caffeine have a neutral pH.

    My pH quick and dirty obviously isnt a goer as it should be neutral pH.....doh!!!!

    I think this is the answer....but it doesnt describe getting the caffeine out of the solution....

    http://antoine.frostburg.edu/chem/senese/101/matter/faq/decaffeinating-coffee.shtml

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    Re: caffeine -- how do they test?

    Nothing dangerous about this one and it could be what you require.

    http://www.seriaz.org/downloads/4-caffiene.pdf

    However weighing to 0.001g is going to cost you!!

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    Re: caffeine -- how do they test?

    Quote Originally Posted by NakedBean link=1183731910/0#11 date=1183890194
    ...out of the question for cost etc, so to would be any chemistry based analytical approach.
    Not sure why youd suggest that? *The chemicals required for an analytical approach are quite low cost ~ Id guess at considerably less then $100, which would go toward a reasonable number of samples. *Only other requirement is a bit of glassware which should be readily available with alternatives likely to be substituted.

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    Re: caffeine -- how do they test?

    My first research indicated both flamable and carcenogenic chemicals and complex chemistry extraction etc which for most people would be out of the question.

    Further research has found a few "simple" chemical methods which could be undertaken "at home" but do require some glassware and precautions but doeable.....

    I dont think this would fall into anything as dangerous as making nitro at home as a 12 year old!! I have only recently found out what I was doing wrong all those years ago and why I nearly always ended in disaster!! In fact I should have died many years ago as a kid, looking back on all the experimenting things I did. How my parents survived all that must have just been good luck.....

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    Re: caffeine -- how do they test?

    Quote Originally Posted by Andy Freeman link=1183731910/0#9 date=1183821544
    Normally, high-performance liquid chromatography separation48 and UV spectrophotometric detection 9,10 methods are applied to both regular and decaffeinated green and roasted coffees for caffeine content determinations. Also, other methods such as capillary electrophoresis,1114 thin layer chromatography
    15 and gas chromatography,16 are used for separation of caffeine in the analysis of mixtures, combined with several other detection methods such as mass spectroscopy16 and FTIR spectrophotometric measurements.1719 However, very costly instrumentation, highly skilled technicians and complicated and time-consuming procedures are required for such methods.

    The local uni that you used to work at andy will be your best bet. We have all of the aforementioned equipment in the biochem labs at my uni. I would say however that you wont be needing highly skilled technicians as you could easlily use 2nd yr students to perform these tests with say 10 samples each in a matter of 1-3 hours depending on the student ;D
    If you get stuck and your ex work wont help let me know.

  18. #18
    CoffeeSnobs Owner Andy's Avatar
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    Re: caffeine -- how do they test?

    "flamable and carcenogenic"?

    Flammable is ok, carcinogenic you can keep. ;)
    I know someone who used to have a jar of hand cleaner, he said "best cleaner I have ever used but I cant get it from work any more"
    twas benzine! **shudder** Irony has it he later died from another horrible disease but not the "big C".

    " 2nd yr students to perform these tests "

    Cool. 2nd year students work for beer. Ill let you know if we need to find some.
    :)

  19. #19
    Super Moderator Javaphile's Avatar
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    Re: caffeine -- how do they test?

    Quote Originally Posted by NakedBean link=1183731910/0#13 date=1183892301
    Nothing dangerous about this one and it could be what you require.

    http://www.seriaz.org/downloads/4-caffiene.pdf
    Hhhmmm....Not quite the case. This process uses methylene chloride which has many nasty side effects (heart, kidney, and liver problems) and has been classified as a probable human carcinogen by the EPA.

    More information available here: http://www.epa.gov/chemfact/s_dcm.txt


    Java "Fun with Chemistry!" phile

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    Re: caffeine -- how do they test?

    We isolated caffeine from tea in a chem subject back in second year, I dont remember exactly what was involved but it wasnt that hard but I imagine itd be a little difficult to guarantee accuracy if youre doing it at home...

    We refer a lot of our water sampling to ALS Laboratories, who also have a food group. Might be a bit costly though

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    Re: caffeine -- how do they test?

    Quote Originally Posted by Javaphile link=1183731910/15#18 date=1183929395
    methylene chloride which has many nasty side effects (heart, kidney, and liver problems) and has been classified as a probable human carcinogen by the EPA.
    Best not have any decaf coffee then, as its quite likely that it was soaked in the stuff (DCM) to remove the caffeine. :o

    Not suggesting anyone here would drink decaf... *:P

  22. #22
    Super Moderator Javaphile's Avatar
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    Re: caffeine -- how do they test?

    Quote Originally Posted by mylesau link=1183731910/15#20 date=1183945632
    Quote Originally Posted by Javaphile link=1183731910/15#18 date=1183929395
    methylene chloride which has many nasty side effects (heart, kidney, and liver problems) and has been classified as a probable human carcinogen by the EPA.
    Best not have any decaf coffee then, as its quite likely that it was soaked in the stuff (DCM) to remove the caffeine. :o

    Not suggesting anyone here would drink decaf... :P
    Working with something that has in the past been exposed to methylene chloride with the MC then removed is hardly the same thing as working directly with pure MC.


    Java "Why bother with Decaf?" phile

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    Re: caffeine -- how do they test?

    Quote Originally Posted by Javaphile link=1183731910/15#21 date=1183946144
    Working with something that has in the past been exposed to methylene chloride with the MC then removed is hardly the same thing as working directly with pure MC.
    Yes! *Sorry I was attempting humour *:(

    More humour -> Of course everyone knows that coffee contains many carcinogens? *;D

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    Re: caffeine -- how do they test?

    .......did you know Black Magic contains more caffeine than any other coffee. ....interesting bit of Trivia.I am a human lab rat and enjoy every experiment.

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    Re: caffeine -- how do they test?

    I used to work for a Melbourne based HPLC (amongst other instruments) manufacturer (Varian, if youre interested). Caffeine was one of the standard tests we did, but usually with pure samples.

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    Behmor Brazen - $249 - Free Freight
    Not sure if anybody will pay attention to this old thread I found by accident searching for Nitro Cold Brew but here is an experiment to isolate and measure caffeine. Not exactly kitchen science but not completely impossible for the home scientist. As a high school science teacher (currently without a high school or lab) I plan on trying this one day, for myself as this is university level (not that high schoolers couldn't although somebody would try and drink the concentrate)

    https://drive.google.com/open?id=1u_...CmeUrt6STrh2VU
    matth3wh likes this.

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