Lord of rings - 17-4-2015 at 01:55
Hi!
I have quite silly question.
I want to make really easy and basic extraction from tea leaves, like caffeine, tannines, gallic acid and whatever else.
I'm considering three options
soaking it in cold water
soaking it in hot water
soaking it in ethanol
What is the best method out of three, so my "extract" will not decompose or oxidize?
thanks
violet sin - 17-4-2015 at 03:24
solvent choice determines the extracted species, polar/nonpolar the biggest difference. if the leaves were weighted or held down and out of the way, a
thin layer of cooking oil would block oxygen from entering the surface in a crude DIY manner if using water maybe. or ya know, just cover the solution
with a tight fitting top while leaving as little airspace above the solution as possible should be good. boiling water first would drive out
absorbed gasses more than at ambient temp.
what exactly is the end game here? pure substances, overall/mixed extraction, dry powder or solution(tea)? I'd say pick a target(s), choose the
solvent, check how well temp affects solubility to aid the process, protect from air if need be. check for decomp temps if you plan to heat and drive
off water to get a powder. some extractions respond better in certain pH ranges.
you posted in the fundamentals section so I gave some fundamental advice. hope I'm not insulting some one with all this knowledge already.
Lord of rings - 17-4-2015 at 04:14
My target is just to get the solvent and to extract from tea as much at it is reasonably possible without decomposition. Later on to use the solvent
as reducing agent for various soluble metal salts to determine if tea extract can reduce them to insoluble state.
Sorry my organic chemistry is knowledge is very limited, that's why I'm asking for such advice
violet sin - 17-4-2015 at 04:50
some metal salts can be reduced with things like glucose, alcohol, i think citric acid(?) if that helps at all.
do you know how to effectively search for patents and papers on the subject? I would suggest google patent search, http://www.google.com/?tbm=pts&hl=en or google scholarly search http://www.google.com/schhp?hl=en
try to figure out some of the lingo used by looking in wikipedia( http://www.wikipedia.org/ ) on reduction, redox, solubility etc. then use those words in the search heading with the name of what ever metal salt
you are thinking of using. take a couple blind stabs at it and often times you find stuff that is quite useful, you might not have thought to search
for. also if not finding anything fun, try changing the wording a bit, it helps in some cases
science madness has a library of books that can be useful for the less knowledgeable( and the advanced) http://www.sciencemadness.org/library/
Lord of rings - 17-4-2015 at 06:25
Thanks for ideas, but all I need is advice which one of extraction methods is more suitable (the ones I stated in my first post).
thanks
DraconicAcid - 17-4-2015 at 08:13
Depends on what you want to extract. I'm fairly sure it's easy to extract caffeine from tea, based on vague memories of having done so as an
undergraduate experiment.
Try one of these: https://www.google.ca/search?btnG=1&pws=0&q=extracti...
(Actually, I misremember. We measured the amount of caffeine in our tea using spectrometry, we didn't isolate it.)
aga - 17-4-2015 at 10:45
Given the low price of tea, plastic drinking cups, hot water, ethanol and Cling Film (to act as a 'lid' on each cup) why not just do an experiment
with 3~5 cups of each one ?
Write everything down (weight, volume, temperature) and do a scientific experiment to find out the answer for yourself.
Chances are that we'd be learning something from your results !
Lord of rings - 17-4-2015 at 10:54
thanks for everybody for their replies
ethanol is my choice. since the chances are ethanol may oxidize before anything else
thread may be closed
violet sin - 17-4-2015 at 11:14
Lord of rings: the reason I added more info is because the question in your opening post is vague. how about you look at the targets and decide
yourself if they need hot water, cold water or alcohol... and if you don't feel like doing the reading, just try all three and see where it get's ya.
you are basically making tea, sun tea or tincture of tea. how will the alcohol affect your plans down stream? these are simple questions with
little reading involved, so get reading or get busy.
dangit, left computer open with out submitting this, finally pressed send, and there have been other comments between 
[Edited on 17-4-2015 by violet sin]
aga - 17-4-2015 at 11:14
Best of luck with the experiment.
It'd be nice to hear about any results (good or bad).