How can I remove acids from cola?

Question

I would like to taste Pepsi-cola without acid. I like it's flavor but don't like acidic taste. It's acidity comes from carbon dioxide, phosphoric and citric acids (see ingredients list in wiki and answers to this question). Carbon dioxide can be evaporated easily. How can I get rid of phosphoric and citric acids? Preferably without expensive lab equipment and hard-to-get reagents.

Edit: Found one recipe by Josh Velson on quora site. He advises adding limewater until the pH reaches about 12.32. Are there any other methods?

Answer 1

You can't remove the acids, because they're dissolved in the liquid. You can, however, neutralise it.

Acid is basically $\ce{H+}$ ions dissolved in the water. By reacting it with a base, you do the following reaction:

$\ce{H+ + OH- -> H2O}$

So the acid reacts to form harmless water.

The problem is that you can't just add $\ce{OH-}$, you have to add it as some salt. Also, the citric and phosphoric acid you have in the cola were added are also dissociated from a salt or molecular form:

$\ce{H3PO4 -> H+ + H2PO4−}$ for phosphoric acid, for instance.

So whatever you put in there that reacts with the $\ce{H+}$ should also react with the $\ce{H2PO4−}$ ion to make something that's not soluble.

Usually, neutralising acids is done with carbonates such as sodium carbonate or calcium carbonate (also known as soda and lime, respectively). Both of which are safe materials to handle. The problem is that by doing that, you're introducing carbonate ($\ce{CO_3^2−}$) which might alter the taste.

A better solution is to add in hydroxides, such as sodium or calcium hydroxide ($\ce{NaOH}$ or $\ce{Ca(OH)2}$). The problem is that those are much more hazardous things which can easily hurt you if you don't use them properly. I would recommend using calcium hydroxide because then the calcium will react with the phosphate anion in the cola to make insoluble calcium phosphates and with citrate to make (somewhat) insoluble calcium citrate. Then you can just filter the stuff out and have your acid-free cola.

Basically, by adding in $\ce{Ca(OH)2}$ to your cola, you react the "acid" bit to make water, and you react the "phosphoric" and "citric" bit to make a white solid precipitate in the bottom of your glass.

DISCLAIMER

This is all in theory. I highly recommend against adding chemicals to your food and drink. If you don't like the acidic taste of cola, don't drink it. Find another brand or another drink that you do like. Tea? Anyway, do not mess with your food unless you know exactly what you're doing and you know that your chemicals are food-grade and safe. Don't go and do stuff with your cola just because someone on the internet (me) told you it will work.

Answer 2

Just get simple and use plain ol' grocery store baking soda. Who cares about why? If you don't add too much, you can defeat the acidic taste and after bite without affecting the Pepsi cola syrup taste. For anything from 12 oz. to 1 litre, add 1/16th teaspoon. Try it to see how you like the taste, then move the amount of baking soda up or down to make it 'perfect'. Baking soda, bicarbonate of soda, NaHCO3, is used as a pH buffering agent. Although another name for it is sodium acid carbonate, its pH in an 0.1 mole solution is 8.3. Therefore, it is mildly basic and can be used to estimate an amount to reduce the acidity of a cola soda water. Start with a 'pinch' and the amount can be titrated up to reach a pleasing taste for your soda.