Fizzy Water - Why Carbonated?

Why is CO2 the preferred agent in fizzy water rather than plain old atmospheric air?

Do nitrogen and oxygen not dissolve as easily in water? Not taste as good? Is it simply tradition?

What sort of pressures are involved?

As I write this, I imagine a real chemist is also composing a response - which is well.

I think it’s got to do with the carbon dioxide forming a mild acid (!) with the water when it disolves. This produces a a taste with some bite to it that other disolved gases don’t produce.

Also, it fizzes a bit. It’s an interesting effect.

Soda springs exist in nature (See: Source Perrier), and artificial carbonation is the most successful method of reproducing the fizz and flavor.

I’m not a scientist, but I’ve heard that nitrogen doesn’t dissolve in water, that water flow is measured by bubble gauges that rely on this trait. Oxygen dissolves in water, but doesn’t produce that neat fizz.

Or digging one up from 2003: Why CO[sub]2[/sub]?

Thanks Squink. I googled but in my frenzy of curosity failed to search the board. whoops.

I am still curious though. I think an experiment with some fittings and a pop bottle are in order.

I’m sure part of it is the fact that more Carbon Dioxide can be dissolved in water as its temperature is lowered, allowing it to be both cold and fizzy.

I suspect the origin is that many drinks naturally produce CO[sub]2[/sub]. You mix the appropriate things together, maybe let them sit for a while, and if it produces a gas, it’s probably going to be carbon dioxide.

According to James Burke’s Connections, the guy who first introduced soda water to the world made it by pouring water back and forth over a vat of fermenting beer, which was, of course, pumping out the CO2.

In general that’s true of all gases, though, in contrast to solids, which generally become more soluble as water temperature increases.

Nitrogen will dissolve in water, which causes “the bends” when divers ascend too quickly, and the dissolved nitrogen forms bubbles in the tissues of the body.

Apart from beers, you can also make “natural” sodas by putting a little bit of yeast into a flavoured, sugared solution in an airtight container. Yeast naturally convert sugar to CO2.

That makes sense. My chemistry teacher only covered CO2 and I must have inferred that other gasses were different.

That’s not actually apart from beer, though. The yeast will also produce alcohol as part of the same reaction. So if you want your water to be as fizzy as beer, it’ll end up as alcoholic as beer, too.

Not really true. Based on homebrewing experience - When beer is fermenting, you let the CO2 escape - the yeast produces way, way more CO2 than you need or want for carbonation. When it comes time to bottle, the beer is pretty much as alcoholic as it’s going to be, but also flat. You mix a small amount of malt or sugar into the big bucket of flat, alcoholic beer, and fill the bottles. The small amount of new fermentables in each bottle will be consumed by the yeast, producing CO2 in the sealed bottle.

I haven’t brewed in a while, but IIRC, the amount of malt for brewing 5 gallons is on the order of 10 cups, while you add less than a cup for carbonation. So the carbonating malt accounts for less than 10% of the total alcohol content of the beer.

Huh. I stand corrected. The fizzy water will still be a little alcoholic, though.

Right, natural sodas will always be a tiny bit alcoholic but this is of the range of 0.5% - 1% which is not enough to get anyone drunk.

Along with a bit of ethyl alcohol!

They perfected the naturally alcoholic soda water in Rio.

My memory from my home-brewing days is that the teaspoon or so of sugar used at bottling produces about 0.5% alcohol by volume (of course, this is on top of the 45 or 5% already in the brew). It’d take rather a lot of naturally fermented soda to get drunk. I suspect it wouldn’t be possible, and your bladder would hate you.

Actually, that’s not quite true. Soft drink is generally pressured in the bottle at an atmosphere or two higher than beer, IIRC. So to get natural soda water, you’d need more sugar, and would probably be getting up into light beer territory in terms of alcohol. Maybe 2% alc/vol.