Chemistry Help Energy Drink

[aeviaanah]

I am looking to reverse engineer Redbull energy drink and brew something similar. I am able to reference the back of can, nutritional facts and general online searches to solve for grams/oz of caffeine, taurine, vitamins etc. Where I am stuck on is pH and additions that affect pH such as the carbonated water, baking soda, magnesium and citric acid.

The wiki source below mentions Redbull prepares a buffer solution of carbonated water, baking soda and magnesium carbonate. When I google/youtube "buffer solution" there seems to be some science here I don't understand. I understand the finish pH needs to be around 3.3. I assume the baking soda and magnesium carbonate are base and will raise the pH.

Questions:
How to make a buffer solution using the ingredients listed above?
How much magnesium carbonate?
Can I use grams of sodium from back of can to solve for baking soda addition (by means of sodium contribution)?
Would I add carbonated water, baking soda and magnesium carbonate and then add the citric acid to pH of 3.3?

The wiki source is below

"Depending on the country, Red Bull contains different amounts of caffeine, taurine, B vitamins (B2, B3, B5, B6, B12) and simple sugars (sucrose and glucose) in a buffer solution of carbonated water, baking soda and magnesium carbonate (substituted in some flavours with a trisodium citrate/citric acid buffer, each solution providing electrolytes).[40][41]"

 

[bracconiere]

well i think you need to investigate learn about terms like pKa, pKb...magnesium carbonate on one hand would be very slow to react with an acid, unless you try and boil it to force it to happen? but would still effect ph, and resist changes in it....

i doubt they use baking soda? probably washing soda?

if i was thinking like you, and what i think you're looking for that energy drink twang....trisodium citrate would sound plausable?


and for the vitamins i'll tip you a link...

they at fair prices, 500g pouches...yes they have bile isolate too!

 

[Lampy]

I looked up the RedBull ingredients and the only listed source of sodium seems to be the sodium bicarbonate (NaHCO3). So I would guess that this means that we can convert 0.24 g Na to about 0.01 mol Na to about 0.88 g NaHCO3 per 20 oz can. My back of the napkin math suggests that this results in a 9.4 pH in a solution of only NaHCO3 and water at this concentration.
I don't remember/don't know how a buffer with MgCO3 would be made, but I think that some guesswork can be done. Assuming that all the sodium in a 20 oz can is from the NaHCO3 and knowing that there are 0.171 g of caffeine in a 20 oz can, we know that the amount of MgCO3 must be between 0.171 - 0.88 g per 20 oz can because it is listed between the caffeine and NaHCO3. Not a narrow range, but its something.
Barring advice from greater minds, I think a good idea would be to use 0.88 g NaHCO3 per 20 oz and a lesser amount of MgCO3 and then add citric acid to reach the appropriate pH.

 

[aeviaanah]

magnesium carbonate on one hand would be very slow to react with an acid, unless you try and boil it to force it to happen? but would still effect ph, and resist changes in it....

They mention they use carbonated water for the buffer. I wonder if this would suggest they do not boil it...wouldnt that drive off the co2?

i doubt they use baking soda? probably washing soda?

if i was thinking like you, and what i think you're looking for that energy drink twang....trisodium citrate would sound plausable?

I didnt see trisodium citrate on the can so I'm a bit weary to toss that in...I have no clue what reactions could occur. Tho the wiki link says they use it "in some flavors" Perhaps the citric acid and vitamins give it the twang? The baking soda is listed right on the back of the can

I looked up the RedBull ingredients and the only listed source of sodium seems to be the sodium bicarbonate (NaHCO3). So I would guess that this means that we can convert 0.24 g Na to about 0.01 mol Na to about 0.88 g NaHCO3 per 20 oz can. My back of the napkin math suggests that this results in a 9.4 pH in a solution of only NaHCO3 and water at this concentration.

Can you explain to me how you converted .25grams Na to grams of Sodium Bicarbonate using mol?
:edit: I was able to youtube this and figure out what you did here. Thankyou!

I don't remember/don't know how a buffer with MgCO3 would be made, but I think that some guesswork can be done. Assuming that all the sodium in a 20 oz can is from the NaHCO3 and knowing that there are 0.171 g of caffeine in a 20 oz can, we know that the amount of MgCO3 must be between 0.171 - 0.88 g per 20 oz can because it is listed between the caffeine and NaHCO3. Not a narrow range, but its something.
Barring advice from greater minds, I think a good idea would be to use 0.88 g NaHCO3 per 20 oz and a lesser amount of MgCO3 and then add citric acid to reach the appropriate pH.

It seems theres a wide range of magnesium contents used in various releases/flavors of redbull

A google search says theres 11mg magnesium in a 12fl oz can. Using the method you revealed above, I'm coming up with 38mg of magnesium carbonate per 12fl oz. Check my math? Seems like this source may be referencing sugar free or something similar considering it is listed before Caffeine on the ingredients.

Using another approach...

RDA: The Recommended Dietary Allowance (RDA) for adults 19-51+ years is 400-420 mg daily for men and 310-320 mg for women.

12% Daily Value Magnesium per 8.4fl oz (from google). I'm coming up with approx 49g magnesium (men) and 38mg (women). Averaging this out I'm sitting around 44mg magnesium in 8.4fl oz. Using the method you showed me above this is approx 152mg magnesium carbonate/8.4fl oz. (again check my math). This methods puts us between the Caffeine and Sodium Bicarbonate amts as listed in order by mass.

Thoughts?

 

[bracconiere]

This methods puts us between the Caffeine and Sodium Bicarbonate amts as listed in order by mass.

if it has both sodium bicarb, and citric acid...it's just going to get gas? and some sodium citrate salts? why i found it hard to believe it's in it?


i mean you can do a self test on that before you call me stupid, and see what happens if you ad some baking soda to some orange juice?

 

[aeviaanah]

if it has both sodium bicarb, and citric acid...it's just going to get gas? and some sodium citrate salts? why i found it hard to believe it's in it?


i mean you can do a self test on that before you call me stupid, and see what happens if you ad some baking soda to some orange juice?

I wonder if they mix this in a pressure vessel to make the carbonated water?

 

[aeviaanah]

Since you are mixing a carbonate with an acid, the reaction will be driven forward through the removal of product (viz. Carbon dioxide bubbling out).

Magnesium carbonate has one divalent magnesium ion. Citric acid has 3 acidic protons. Therefore, for every two molecules of citric acid, you need three magnesium ions. Hence, these don't react in a 1:1 ratio in any capacity. To convert all the magnesium and all the citric acid to magnesium citrate, and therefore have no left over reactant, you need to solve the stoiciometry.

For calculation of reaction products: One mole of citric acid weighs 192 g. If you're unsure of this concept, I highly recommend you read about moles. Thus, the two moles weigh 384 g.

One mole of magnesium carbonate is 84 g. Three moles is 252 g.

Thus, for every 384 g of citric acid, you need 252 g of magnesium carbonate. This will create 451 g of the magnesium citrate. Since you are a software engineer, I'm sure you're familiar with scaling this down with proportions

I wonder what this would do to pH? Finished pH needs to be 3.3. @Silver_Is_Money

 

[bracconiere]

I wonder what this would do to pH? Finished pH needs to be 3.3.

once again have to get into normality...how many hydrogen atoms are lonely to how many atoms want to get taken...and the BMI of them all.....called normality....

 

[Lampy]

A google search says theres 11mg magnesium in a 12fl oz can. Using the method you revealed above, I'm coming up with 38mg of magnesium carbonate per 12fl oz. Check my math?

I checked, this works out.
So if we assume all the listed sodium and magnesium on the nutrition label come from NaHCO3 and MgCO3 respectively, then you get roughly:
38mg/12oz = 3.2 mg per oz of MgCO3 = 410 mg MgCO3 per gallon
880mg/20oz = 44 mg per oz NaHCO3 = 5.6 g NaHCO3 per gallon

To which you add other minor ingredients (caffeine, etc) which will affect pH, then add the citric acid to reach the desired pH.
I would suggest doing a small test batch of buffer with the MgCO3, NaHCO3, and citric acid just to see if these numbers can work and if they do, is the result just plain nasty?

 

[aeviaanah]

I checked, this works out.
So if we assume all the listed sodium and magnesium on the nutrition label come from NaHCO3 and MgCO3 respectively, then you get roughly:
38mg/12oz = 3.2 mg per oz of MgCO3 = 410 mg MgCO3 per gallon
880mg/20oz = 44 mg per oz NaHCO3 = 5.6 g NaHCO3 per gallon

To which you add other minor ingredients (caffeine, etc) which will affect pH, then add the citric acid to reach the desired pH.
I would suggest doing a small test batch of buffer with the MgCO3, NaHCO3, and citric acid just to see if these numbers can work and if they do, is the result just plain nasty?

Thanks for checking. What your describing is similar to what my plan currently is. I'm now stuck on the reactions between citric acid and magnesium carbonate and the fact that magnesium carbonate is insoluble with water.

 

[Lampy]

Thanks for checking. What your describing is similar to what my plan currently is. I'm now stuck on the reactions between citric acid and magnesium carbonate and the fact that magnesium carbonate is insoluble with water.

Well the reaction would be expected. That's what a buffer is for - it reacts with acid (or base) to neutralize it and prevent pH shifts. However, because we know from the ingredients list that citric acid is a larger proportion than the buffer components, I imagine it will eventually deplete the buffer and the pH will drop.
I think that the citric acid reaction with the magnesium carbonate will help it dissolve. Post your results please - I am curious about how the tests/final product comes out.

 

[aeviaanah]

Well the reaction would be expected. That's what a buffer is for - it reacts with acid (or base) to neutralize it and prevent pH shifts. However, because we know from the ingredients list that citric acid is a larger proportion than the buffer components, I imagine it will eventually deplete the buffer and the pH will drop.
I think that the citric acid reaction with the magnesium carbonate will help it dissolve. Post your results please - I am curious about how the tests/final product comes out.

I'm having a hard time understanding why a buffer is used only to be depleted. What are your thoughts on them using the reaction to carbonate?

I'll post the results

 

[AlexKay]

Something isn't right with this information. pH 3.3 is really pretty acidic -- more acidic then you'll get from the carbonation (which would be ~4.5, and remember that 3.3 is 16 times more acidic than 4.5), and adding bicarbonate and carbonate will only raise the pH from there.

 

[Lampy]

Something isn't right with this information. pH 3.3 is really pretty acidic -- more acidic then you'll get from the carbonation (which would be ~4.5, and remember that 3.3 is 16 times more acidic than 4.5), and adding bicarbonate and carbonate will only raise the pH from there.

It is true, 3.3 is quite acidic, but it is not unheard of for commercial beverages, see here. The carbonation itself might not drop pH that low, but added acidic ingredients can.

Where I see a possible problem is that because the bicarbonate and carbonate will prevent the pH from fall until depleted, it might take a fairly large amount of acid to reach 3.3. However, once the buffer is depleted the pH should fall quite quickly.

I'm having a hard time understanding why a buffer is used only to be depleted. What are your thoughts on them using the reaction to carbonate?

It might be that with the desired ingredients the pH would be too low without a buffer. I doubt that the reaction is used to carbonate the drink commercially, it is probably just force carbonation.
I did some rough calculations using pV=nRT and assuming all carbonate and bicarbonate get converted to CO2 you would only get an extra ~0.62 atm of extra pressure - not very much compared to the ~3 atm in carbonated beverages.
This could be another thing to test in your experiments, but it would only work if the reaction takes place in a sealed vessel.

 

[aeviaanah]

It is true, 3.3 is quite acidic, but it is not unheard of for commercial beverages, see here. The carbonation itself might not drop pH that low, but added acidic ingredients can.

Where I see a possible problem is that because the bicarbonate and carbonate will prevent the pH from fall until depleted, it might take a fairly large amount of acid to reach 3.3. However, once the buffer is depleted the pH should fall quite quickly.


It might be that with the desired ingredients the pH would be too low without a buffer. I doubt that the reaction is used to carbonate the drink commercially, it is probably just force carbonation.
I did some rough calculations using pV=nRT and assuming all carbonate and bicarbonate get converted to CO2 you would only get an extra ~0.62 atm of extra pressure - not very much compared to the ~3 atm in carbonated beverages.
This could be another thing to test in your experiments, but it would only work if the reaction takes place in a sealed vessel.

Do you think I should warm anything up or do the first test cold?

 

[Lampy]

I don't think heating would be needed. MgCO3 is minimally soluble and even heating up to boiling won't do much.
Note: all the calculations we have here are assuming that you use anhydrous (dry) MgCO3. It naturally absorbs water from the air so it must not be left open for long periods

 

[aeviaanah]

I don't think heating would be needed. MgCO3 is minimally soluble and even heating up to boiling won't do much.
Note: all the calculations we have here are assuming that you use anhydrous (dry) MgCO3. It naturally absorbs water from the air so it must not be left open for long periods

10-4 yes the magnesium carbonate I have is dry and I won't open it till the first test and vacuum seal it after

 

[aeviaanah]

Good chance I'll have some time to brew this next Wednesday. Might start with a 1gal batch or so and scale up from there

 

[aeviaanah]

I did a 1/2 gallon test batch today. Combined a few of the ingredients and measured pH along the way as they were added. I then added citric acid to a finish pH of 3.1. Everything dissolved really well even in 40F carbonated water.

I added a bit of passion fruit extract and all tastes great, just wish it had a bit more carbonation but that's to be expected with all the mixing/driving off co2. I did notice the pH continuing to creep up, likely due to the release of carbonic acid?

I ended up canning a 32oz version of this to share with my partner. If you guys don't hear from me soon, you'll know what did me off!

 

[Lampy]

Great data collection - so methodical! Maybe the carbonation can be better in a future batch now that you know quantities of ingredients and won't have to mix/test as much.

 

[aeviaanah]

Great data collection - so methodical! Maybe the carbonation can be better in a future batch now that you know quantities of ingredients and won't have to mix/test as much.

I'm gonna mix these up using carbonated RO water in three separate 5gal kegs, put on gas similar to carbing a beer and serve.

 

[aeviaanah]

Energy drink came out really good, ended up making a sugar free and sugared version. I made a mistake and added Guarana as my source of caffeine but it ended up giving it good flavor anyway. The second batch I'm gonna sub out Guarana for pure caffeine and rely on natural/artificial flavors to better mimic Redbull..

Thinking about trying Sodium Citrate, would I pull the baking soda in place for this? I think its base.

 

[bracconiere]

Thinking about trying Sodium Citrate, would I pull the baking soda in place for this? I think its base.

i think it would depend on if it's trisodium citrate, or monosodium citrate...maybe just a tweak in how much?

 

[Lampy]

I wouldn't do a full substitution of baking soda for citrate. Maybe just partial. Glad to see positive results.

 

[aeviaanah]

I got some sodium citrate on the way, not sure if it's tri or mono. I'll try a partial substitute I dunno maybe 50/50 by sodium contributions?? Lol

 

[bracconiere]

I got some sodium citrate on the way, not sure if it's tri or mono. I'll try a partial substitute I dunno maybe 50/50 by sodium contributions?? Lol

looking at stuff labeled sodium citrate, probably trisodium....i think it'd have to be labeled mono sodium citrate?

i think i was thinking mono hydrate?

 

[aeviaanah]

looking at stuff labeled sodium citrate, probably trisodium....i think it'd have to be labeled mono sodium citrate?



View attachment 776672

i think i was thinking mono hydrate?

It's the sodium trifecta

 

[bracconiere]

trifecta

sounds like a music festival... at least all the openings are filled..