The Science of Bubbles: How Carbonation Works in Soda

Close-up view of bubbles in a glass of carbonated water

As soon as man discovered how to infuse water with carbonation, people fell in love with the sensation created by the bubbly liquid when it hit their mouth. And why not? There's no other feeling quite like it and for some reason that fizzy feeling seems to make a beverage taste better. But what exactly is going on with the carbonation in soda? How does it get there and where does it go after you leave the can or bottle open for a while? In this post, the team behind Rocky Mountain Soda Company's natural soda put those tiny bubbles under the microscope to see what the heck is going on.

Oh Happiness! They Name is Carbonation

The disconnect between an icy cold soda with its full complement of CO2 and a soda that’s been left open for a while is as close to night and day as things get without actually being night and day. A fully carbed-up soda is a unique and compelling taste sensation that brings happiness to people from 2 to 102. However, once a soda is opened the clock starts ticking on the fizz, and nobody, nobody wants a flat soda. So where does the fizz go? Well, before we explain that phenomenon we need to talk about how the fizz got into the soda in the first place.

Putting the Fizz in Fizzy Drinks

The fizz in fizzy drinks is a result of the liquid being infused with carbon dioxide or CO2. Under normal conditions, it's practically impossible to infuse the liquid with carbon dioxide. In order to get the liquid to accept the CO2, soda manufacturers need to keep the liquid cool and increase the pressure inside the can (or bottle).

So the liquid is added to the can, CO2 is added at a higher than atmospheric pressure and the can is sealed before any CO2 escapes. With the high pressure inside the can most of the CO2 fuses with the water molecules (H2O), while the rest occupies whatever empty space remains.

Keeping a can of soda refrigerated enables the CO2 to dissolve into the liquid easier than it would at room temperature. When you crack open a brand new soda the hiss sound you hear is the pressurized CO2 escaping at a rapid speed.

What Goes on Inside a Can of Carbonated Soda?

Once a can of soda is sealed the contents are under pressure greater than that of the outside air. As a result, if you accidentally poke a hole in the can the contents will spray out under tremendous force until the excess pressure is released. That said, the carbonation in a can of Rocky Mountain Gluten-Free, Vegan Soda doesn’t just sit there waiting anxiously for you to crack open (or puncture) the can so it can have its day in the sun.

Instead, it makes good use of its time by reacting with the water in the soda mixture to form carbonic acid. That carbonic acid will give the drink its slightly tangy taste. A tangy taste that will be lost once the soda is left open too long.

If, by some chance, the can is dropped or otherwise shaken just before opening some of the carbon dioxide in the liquid is released to join the carbon dioxide occupying the empty space in the can. This creates additional pressure inside. As a result, when you open a can that’s been shaken or dropped the contents will explode outward.

Why Soda Goes Flat After Being Opened

Carbon dioxide comprises about .04% of the earth’s atmosphere. (The amount has risen about 25% in the past 70 years which is a major contributor to climate change.) The CO2 contained in a can of soda is much higher than what is found in the atmosphere. When you open the can the CO2 in the liquid sets about finding equilibrium with the surrounding air, which is a fancy way of saying it is gradually released over several hours until the CO2 concentrations in the liquid are the same as in the air. The result is that the fizz is gone.

On a side note, don’t despair that you’re contributing to climate change when you open a fizzy soda. The amount of CO2 released from all the sodas in the world is microscopic compared to the overall carbon footprint of all the world’s people.

Why Does Soda Fizz So Much When Poured Into a Glass?

You’ve no doubt noticed that when you pour soda into a glass you get a veritable fizz-fest. Why is that? It’s because when you transfer the soda from the can to the glass you greatly increase the surface area of the soda that is exposed to the air. More surface area means more CO2 is able to escape. And it’s the escaping CO2 that creates the extra fizziness.

Why Does Fizzy Soda Taste Better Than Flat Soda?

Everyone knows that when you leave an open soda laying around for a few hours it goes flat. The strange thing is that when the fizz escapes it seems to take the flavor with it. But how can this be?

Remember the carbonic acid we mentioned a little earlier in this article? It’s created by the interaction of CO2 and water in the soda mixture. Well, that carbonic acid creates a tingling sensation on the tongue that makes the beverage taste a little extra tangy. Once all the carbonic acid escapes there is no more tingling sensation or tanginess and you’re left with just the raw materials of the soda mixture, which normally depend on the CO2 to bring them to life.

Enjoy the Fizzy Freshness of Rocky Mountain All Natural Soda

We hope the above information has helped clear things up for you about what carbonation is and how it works in relation to your favorite soft drink.

If you’re in the market for a kosher, vegan, soda with no GMOs (but plenty of fizz!) order natural sodas online from Rocky Mountain Soda Company. They're made with both the environment and our customers in mind.