NEMO-Chemistry
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Coffee extraction
Had a good look around the net, seems to be loads of ways to extract Caffeine. Some good sources say to do a Sodium Carbonate extraction first, some
say use Hydrochloric acid.
One uses Sodium hydroxide (actually this one had the best yield), solvents used include DCM, Ethyl acetate, Chloroform. None the yields are stella, no
agreement on best method except to use pills.
So i been out and got some Coffee, its the pre ground NON instant stuff for machines. Over the weekend I am going to do this and see what works best.
I might use Methanol, DCM and Chloroform or IPA. I will also try some different techniques like soxhlet with no water just solvent.
I also want to see what agent is best for salting out the Caffeine.
The other extractions over the next few days include, Nutmeg from whole nutmegs, Cinnamon from the sticks and Eugenol from cloves.
These i often do for soap making, or for wax stuff etc, but i havnt played around with the variables much. I will use TLC each time to see what
solvent pulls out the goodies best.
I should have Hexane as well next week.
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Corrosive Joeseph
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"The solubility of caffeine in water, ethyl acetate, ethanol, carbon tetrachloride, methanol, chloroform, dichloromethane and acetone were measured by
a gravimetrical method from (298 to 323) K and the solubility data was correlated against temperature. The solubility of caffeine in chloroform and
dichloromethane was high compared with other solvents."
Solubility of caffeine in water, ethyl acetate, ethanol, carbon tetrachloride, methanol, chloroform, dichloromethane, and acetone between 298 and 323
K. Available from: https://www.researchgate.net/publication/262549582_Solubilit... [accessed Dec 16 2017].
" Caffeine can be dissolved in organic solvents such as ethyl acetate, chloroform, ethanol, carbon tetrachloride, methanol and dichloromethane.
According to the literature studies, solubility of caffeine in chloroform shows higher value than the other solvents. Therefore, chloroform is a
better solvent to separate and purify caffeine from solutions[28]. For this reason, chloroform was used in the extraction of caffeine from tea."
Determination of lemon and carbonate effects on caffeine content of various teas
https://www.researchgate.net/publication/308827421_Determina...
I look forward to your results........ Alcohol soxhlet is very interesting
/CJ
Being well adjusted to a sick society is no measure of one's mental health
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NEMO-Chemistry
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Thx for the information, i have done some batches today and will finish off tomorrow. The results were not what I was expecting....
I will post up as soon as I get them all done, i could do with a mantle bank lol.
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NEMO-Chemistry
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I have run out of Chloroform so wasnt going to test it in the end, but reading a paper i found has made me decide to make some more and try it.
So far Methanol has proved useless for Caffeine extraction, this however was expected. The differences seen so far between Acid and Base extraction is
slightly strange. I will detail those when I am finished. I have pics this time!!
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aga
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Boiling hot water also works for caffeine extraction from coffee beans.
I tend to add sucrose and lactose as well before drinking this mixture in the morning 
Acetone or ethyl acetate (nail varnish remover) will probably work.
Give it a try with your soxhlet and let us know how well it goes.
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NEMO-Chemistry
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Quote: Originally posted by aga  | Boiling hot water also works for caffeine extraction from coffee beans.
I tend to add sucrose and lactose as well before drinking this mixture in the morning
Acetone or ethyl acetate (nail varnish remover) will probably work.
Give it a try with your soxhlet and let us know how well it goes. |
I will grab more coffee in the morning and redo some of them as well. I did 4-5 before i noticed something, so now i am intrigued. I have less than
half a pack coffee left, because its not instant coffee, I should repeat with a single coffee bag... Its ok i will post todays results with them, but
will redo them all tomorrow.
I also want to do soxhlet with warm water and warm solvent. That might be tricky with the solvents, but water should be ok. I will use slightly warm
water in the condenser jacket.
Seeing as caffeine is slightly basic, you would expect acid extraction to work better, would you not? But coffee itself is slightly acidic...
the original idea was just to practice extractions some more, plus i wanted some caffeine for some experiments, but this has turned out to be more
interesting than i thought.
I wonder what happens chemically if you add the lactose before the extraction . I
forgot i have toluene (not had it before), i will try that as well tomorrow. My temperatures might be off, i dont trust the new thermocouple.
Back to a real thermometer I think.
Quick question..........
What would the best solvent combination be for TLC? And are there any wet tests for caffeine? Or better yet, is there anyway I can titrate the
caffeine?
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aga
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| Quote: Originally posted by aga | Acetone or ethyl acetate (nail varnish remover) will probably work.
Give it a try with your soxhlet and let us know how well it goes. |
Maybe actually Doing something rather than endless speculation would be more interesting.
Maybe not. Who knows ?
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NEMO-Chemistry
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| Quote: Originally posted by aga | | Quote: Originally posted by aga | Acetone or ethyl acetate (nail varnish remover) will probably work.
Give it a try with your soxhlet and let us know how well it goes. |
Maybe actually Doing something rather than endless speculation would be more interesting.
Maybe not. Who knows ? |
Read it again....
I have done it, i am redoing some and adding some more to what i have done TODAY already.
Then I will write it up with PICS.
Acetone I did TODAY, ethyl acetate i dont have and besides i think 6-7 solvents are enough.
Thats 21 extractions, 6 are done. So what exactly did you DO today chemistry wise?
[Edited on 16-12-2017 by NEMO-Chemistry]
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NEMO-Chemistry
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After much reading..Seems first step is to get the caffeine out of the coffee, it looks like the best way is simply heat it for hours and then leave
over night.
I found a table that suggest only 10% is extracted after an hour of heating, the process with making decaf can take upto 14 hours of re fluxing, but
this was for green beans...
So make a large pot today and stand for a day or so. The soxhlet stuff I can do today however, I could do with a small condenser, and use two of them,
one at the top to condense and one at the bottom to warm the solvent up a bit as it returns to the soxhlet.
Will see what I can cobble today. Adding Sodium Carbonate or Hydroxide seems to stop alot of the crap going into the organic layer, i will try
Carbonate as I dont fancy heating hydroxide on my glass for hours  .
Once i got my pot of coffee, I will also try salting out, so if I can get some the crap out that way, might be an idea to use Methanol and water mix
for this, but then you increase emulsion formation.
Yes i could simply follow what everyone has done, but then thats just going to give me the same results!
[Edited on 17-12-2017 by NEMO-Chemistry]
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NEMO-Chemistry
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Coffee simmering away under reflux for the last 4 hours, i am switching to 2 hours heating and then an hour cooling for a bit. The liquid is getting
darker and darker, one pot has sodium carbonate in, the other dosnt.
I only have 2 hot plates free, so making coffee is my limit for today. Crushed my Chlorine tablets, but they refuse point blank to dissolve!! They
dont smell much like chlorine either, i got them unopened about a week ago so dont think they are old...Then again they looked repacked.
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NEMO-Chemistry
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I have done some of these extractions a number of times now, i keep getting non consistent results. I am trying to keep the variables to a minimum,
such as using the same packet and brand of coffee each time.
Its impossible to know the % yield without knowing how much is in the material to start with!! As a last ditched attempt to get a reasonable base
line, I have been looking at CO2 extraction. Now I am not going to use CO2, various reasons but the main one being it isnt actually that easy for me
to get liquid CO2.
So I am going to resort to Lighter gas, Butane I think it is. I am aware this is used by happy smokers, so it should work on coffee . I have a can so will do 3 extractions with it on 25G coffee each, whatever the
result that is going to be my base line.
This should have been really simple, but i ended up over thinking it and turning it into a fucking crusade! Havnt decided on the final set up for the
gas extraction, although for obvious reasons i will do it outside .
My money is still on Chloroform being the best, but again getting chloroform (something i have made alot of in the past) is being a PITA to make at
the moment!
I did get good results with the soxhlet and Toluene which surprised me, i was keeping the soxhlet thimble warm with a heat gun though. 2-3 hours
tomorrow is my time span. Then I doubt i will get much time until day after boxing day  . I will get this thing finished and posted with pics!!!!
I am not complaining though, i order 2 ltr of methanol from ebay, as i had used all mine up doing some the extractions. However when it was delivered
today I found a 20ltr drum on my door step . I called them up and explained
they had messed up, although they have only charged me for 2 ltr, they have said I can keep the drum . I guess its cheaper to do that than have it
shipped back, plus they now got a happy customer .
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NEMO-Chemistry
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A miserable fail at distillation! I got a new to me heating mantle, but the heat knob isnt working properly, i will take apart and try and fix it. It
keeps tripping the electric, so doing this last night was a nightmare!! Pitch black trying to find my way around the house to the fuse panel!!
I am really regretting starting this project, its really not fun any more!! But i want to finish it more than ever now. I doubt i will ever revisit
this particular extraction! Fingers crossed i will finally get aga his pics today!! Getting him pics is the only thing keeping me from throwing this
coffee out!
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NEMO-Chemistry
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I managed a pic with a phone, the problem normally however, i use this phone to tether to the internet! So when in the lab i can get a signal, so i
cant use my tablet to look stuff up and take pics!
I got the tablet cheap because it has a camera on, but the camera is utter shite!! The tablet also dosnt take a sim card . anyway on with this!
The point of the exercise isnt just to get some caffeine, if it was i would have given up and brought some long ago! partly its to look into some
discrepancies I found in various papers. Also much of the extraction work that has been done, has been from a commercial view point, the need to keep
flavors in etc.
I have different goals in mind, i also wanted to answer a basic question, a coffee machine in a cafe generally uses the same beans, it also uses the
same amount each time. So how come the caffeine content for a normal coffee is in the low mg, and for say a double espresso its over 1 gram?
The espresso thing also got me thinking, i found a paper that stated some espresso samples contained over 1.4g of caffeine, i assume this is because
pressure is used and a slow speed. I also found papers that stated caffeine is protonated with a ph above 8 and some that said there was no
difference.
Many papers said decaf coffee still contained caffeine! When you look at solubility there is little difference at room temp between Ethanol and water,
Chloroform at 25C seems to have the greatest solubility.
And on and on and on, the questions keep popping up, so hence why i am doing coffee experiments. I also have other reasons, a couple of them i wont
mention yet, but i would like to separate some other components of coffee, maybe find a decent method for amateurs to get a good yield from spent
coffee whats its.
Then we come to Tea.... I have alot of reasons why i want to look into Tea and its contents, but that a whole other thread! I have started a webpage
on these experiments, i will do a complete summary here once completed though.
One the things I have been doing is collecting coffee from the coffee maker and putting it into several gas jars, its sits there for weeks! every now
and then I filter and concentrate, then put it back into the jar. I will explain more about all this later, but seeing as I have a way to take pics
today, here is a pic of one the jars!
The coffee has been in there from day one of this thread, i concentrate it then top back up with fresh water.
Current pH is around 4.7-5
Anyone know what the best solvent combination would be, to develop Whatman K5 & K6 cellulose TLC plates with coffee? i want to track what solvents
remove which components.
I will post the web address to the complete set of experiments once I have it in better shape. i will also post the pics here. this is a fairly long
term experiment however.
![20180101_152624[1].jpg - 1.3MB](http://www.sciencemadness.org/talk/files.php?pid=502141&aid=63722)
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