I saw on Youtube a video where caffeine was extracted from Red Bull using dichloromethane. However, due to dichloromethane tendency to form emulsions with liquid, an inefficient method was used to mix the dichloromethane and the Red Bull to minimize the emulsion.

The video maker stated that an emulsion can be broken by adding a salt, but a salt would also drastically affect the taste of the final product. I was wondering, are there any tasteless edible salts that could have been used to break the emulsion without affecting the flavor?

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    $\begingroup$ Interesting, I found that magnesium salts taste bitter, also this would give you diahrrea $\endgroup$ – Cody Aldaz Jul 6 '20 at 6:12
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    $\begingroup$ I found boron phosphate and (KCl?) from the comments of this previous question as an example of an odorless an tasteless salt (is it edible? Don't think so!) $\endgroup$ – Nilay Ghosh Jul 6 '20 at 8:19
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    $\begingroup$ SAFETY - I wouldn't taste the extract, and I surely wouldn't drink it. There will be some DCM in the aqueous phase. $\endgroup$ – MaxW Jul 6 '20 at 17:40
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    $\begingroup$ @MaxW They extracted the dichloromethane using a vacuum. An hour under the vacuum seemed to be enough to evaporate it all. $\endgroup$ – Bryan Tan Jul 7 '20 at 1:26
  • $\begingroup$ The protocol and the title question are two different things. Adding a salt, even a salty tasting one, helps the extraction by increasing the density of the aqueous fraction and/or via electrostatic effects, depending on the density of the solvent used. The salt is supposed not to be in the targeted organic phase, when the latter is properly washed. $\endgroup$ – Alchimista Jul 7 '20 at 9:18

Giving a cursory Google e-book search gave me results particularly from old textbooks of 19th century:

  1. Phosphate of soda (Sodium phosphate, $\ce{Na3PO4}$) - was sold under the name of tasteless salt
  2. Sulfate of lime (calcium sulfate, $\ce{CaSO4}$) - it was named agustine because this salt was considered to have no taste. It was considered to mix with acids to form tasteless salts
  3. Phosphates of barytes (barium phosphate, $\ce{Ba3(PO4)2}$) - considered tasteless
  4. Phosphate of strontium (strontium phoshate, $\ce{Sr3(PO4)2}$) - considered tasteless
  5. Superphosphate of lime (calcium superphosphate, $\ce{Ca(H2PO4)2}$) - at high temperature, it melts to a semi-transparent glass which is tasteless.
  6. Sulfate of strontium (strontium sulfate, $\ce{SrSO4}$) - considered tasteless

@Ivan said in a comment(deleted) that calcium sulfate, barium phosphate, strontium phosphate and strontium sulfate are insoluble in water, so they cannot serve the purpose of breaking the emulsion. Finally as OP clarifies, calcium superphosphate is corrosive and hence not safe to eat, it all comes down to sodium phosphate which is both tasteless and edible.

References(in order of mentioned points)

  1. London Medical Gazette: Or, Journal of Practical Medicine, Volume 18, 1836
  2. The Critical Review: Or, Annals of Literature, Volume 33 Tobias Smollett, 1801
  3. Pantologia: A New Cabinet Cyclopaedia, Comprehending a Complete Series of Essays, Treatises, and Systems, Alphabetically Arranged, J. Walker, 1819
  4. The Cyclopædia, Or, Universal Dictionary of Arts, Sciences, and Literature, Volume 39, Longman, Hurst, Rees, Orme & Brown, 1819
  • $\begingroup$ Sodium phosphate is indeed edible and is sold food grade. Calcium superphosphate turned up this page: pubchem.ncbi.nlm.nih.gov/compound/Calcium-superphosphate calling it "corrosive" and an "irritant" so probably not safe to eat or drink $\endgroup$ – Bryan Tan Jul 7 '20 at 1:18
  • $\begingroup$ Taste is rather tricky: I have a vial of "P.T.C Paper" test strips "for use in medical genetics", as it says on the vial's label. The strips contain phenylthiourea-phenylthiocarbamide and it is said that people either find the taste extremely bitter (as I do) or completely tasteless. Most people I have tested this on find the test strips tasteless (no pun intended). $\endgroup$ – Ed V Jul 7 '20 at 1:39
  • $\begingroup$ @EdV I think that's the exception that proves the rule. The PTC is famous because there is such a difference in reaction to it, and such striking differences are unusual. Of course, there is individual variation in taste. But, for the most part, the perceptions of bitter/sweet/salty/sour are universal. Very few people don't perceive sugar as sweet, NaCl as salty, lemon juice as sour, etc. $\endgroup$ – theorist Jul 7 '20 at 4:22
  • $\begingroup$ No argument! Still not sure if I ever want to try eating durian, if I ever get the opportunity! ;) $\endgroup$ – Ed V Jul 7 '20 at 11:41

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