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Carbonate drinks with compressed air? Answered

So there are a lot of carbonators out there, and they all cost in the range of $50-$100, which is a lot, but the real cost comes form the co2 cartridges. So I was wondering.... why not just use compressed air? sure, it would take longer for all the co2 in the compressed air to reach equilibrium between the water and the air, but i do believe that if you let it sit for long enough, it would work.

other gasses would also diffuse into the water, like oxygen, but since gasses are hard to taste, it shouldn't make a big difference. (co2 actually forms carboxylic acid, which tastes sour, but i can live with it not being exactly the right taste)

all i have to test this theory is 115 psi from an air compressor... would this be enough?



Best Answer 6 years ago

"but since gasses are hard to taste"

The exact gas(ses) and lack thereof are SPECIFICALLY what makes the taste -- flat pop tastes terrible because that carboxylic acid counters the sweet syrup). It's what provides the burning sizzle.

Yes, you can dissolve other gasses at high pressures, but most just don't fizz. The other benefit to CO2 (and huge detriment to others) is that CO2 is mostly inert at reasonable temperatures, and kills/starves bacteria of Oxygen. Dissolve a bunch of O2 in your drink and see how long it stays fresh!

You can make a carbonator for super cheap; all you need is some tubing, a schrader valve in a cap, and an on/off/bleed valve. The CO2 tank and regulator are arguably the most expensive part, but they're one time purchases, and the gas refills are ridiculously cheap after that. (pennies per litre of carbonated drink).

thx for the response, you have a good point about the oxygen and the freshness of the drink. So i guess it wouldn't taste the same as a normal drink with only carbon dioxide in it, but i bet it would still be interesting.

you said that most gasses just don't fizz when they are dissolved in water. why is that? i thought that any gas, once dissolved, has reached equilibrium, and once the external pressure is lower, it will try to reach equilibrium again, causing the gas to form bubbles and diffuse into the external atmosphere. do the other gasses simply diffuse without forming bubbles?

and you also said making the device would be cheap. i agree, that is not the problem. refills are the problem. would you suggest getting a large welding-type cylinder and getting refills for that?

could you just use a air compressor?

and wouldn't you have to shake it up after there air inside of the bottle

my theory is

put a schrader valve in a cap and screw on a bottle

then put compressed air in.

shake it for 2 mins. then enjoy?

please respond thank you

Not sure, I never did end up trying it. It seems that one problem might be that the Nitrogen and Oxygen in the air is not soluble enough to dissolve a lot in water. CO2 is much more soluble in water. Then again, one of the commenters below mentioned that the company Keurig did make a product that was essentially an air compressor set up like you describe.

I think the only way to find out is to try it! Just make sure you are safe about it, and keep in mind that commercial air compressors often have quite a bit of oil vapor in the airstream - not something you would necessarily want to infuse into your drink. Might need an air filter of some sort to make the water drinkable.

So about 3 years after the question was shot down, Keurig apparently released a contraption that did exactly this. They haven't released a lot of information, but I'm guessing that it has something to do with the fact that CO2 is so much more soluble in water (especially cold water, and note that they did go to a lot of effort to make sure their machine dispensed only cold for some reason) at least according to http://www.engineeringtoolbox.com/gases-solubility... ; I assume that even if air is only 0.03-0.04 per cent CO_2, eventually sufficiently cold water under just the right pressure can absorb enough to become truly "carbonated". The machine also refuses to dispense more than 8 oz. at a time (much less than a 12oz can!) so the freshness-vs-oxygen comment was probably a very salient one.

So I'd have to say this was a pretty darn reasonable question after all. Even if the commercial product has a gotcha somewhere, a *very* expensive claim has still been made that this not only can be done, but has been done.

Wow, that's really interesting! I never did go further with the concept, but it's cool to see that it works, especially since so many people said it wouldn't. Thanks for the update!

**Greetings; I can't reply to a question marked best already;

Poor wording on my part -- when you drop the pressure, yes bubbles will come out, but its the carbon dioxide in those bubbles that has the taste you're familiar with.

Many places 'lend' you the tank -- you just pay a deposit, say 20-50 dollars for a cylinder, then when its empty, you take it back and get it refilled -- might be a rental or a deposit.

interesting, thanks for your help.

i always thought cylinders would be more expensive than that, i heard prices in the range of $350-500... maybe that was only for argon cylinders for mig welding aluminum.

They're called "carbonated" because they're saturated with carbon dioxide.



what i meant was that i was wondering if a similar effect could be achieved.

No. Carbon dioxide has a high solubility on water, to make water fizzy you cram a lot in under pressure.
Oxygen and Nitrogen also dissolve under pressure and that pretty much all you've got in air. But they don't dissolve as much as carbon dioxide 'cos you don't have that acid-base equilibrium.


You know dry ice is cheap.
I imagine if you were to install a big piece of pipe out of the water drain on your compressor with an end cap you could put big chunks of dry ice in there to evap & create loads of C02 pressure...
So the smaller tanks might end up being better suited to your needs.

Better yet just use some stainless steel pipe, tap a valve into one endcap & unscrew the other endcap to load in large pieces of dry ice. Badaboom. :)

interesting idea. the only problem is that i would have to go and buy dry ice every time i wanted a carbonated drink...


6 years ago

There is almost no CO2 in the air which is 78% Nitrogen, 21% Oxygen
and only o.03% Carbon Dioxide.