How Does Carbonation Occur?

That familiar “psst” when you open a carbonated drink is a commonplace occurrence, and we often don’t stop to think about the cause. Sure, we know that things like soda cans are under pressure and that mass of bubbles that rise up come from trapped gases. But beyond the surface level, what’s the science behind carbonation?

1. Part of the answer is in the name.
Carbonation, as the name suggests, is the process of adding carbon to something. More specifically, carbon dioxide gas (CO2) is used. When CO2 is added to water under pressure, it dissolves. This forms carbonic acid (don’t worry, it’s a weak acid).

2. How does that CO2 get there in the first place, though?
Carbonating drinks isn’t as complex as you might think. You know those machines that help you make your own sparkling water? They use the same process that manufacturers use. First, you need carbon dioxide under pressure. Then, you inject it into water (the process is slightly different for products like wine) and hey presto, bubbles!

3. Water temperature matters as far as “fizz” is concerned.
There is an ideal temperature at which carbon dioxide dissolves in water. Warm water allows the CO2 molecules to move faster and thus escape more rapidly. Colder water around 32 degrees Fahrenheit is generally thought to be best, as it provides the perfect conditions for a greater proportion of CO2 to dissolve. This results in more carbonation, and consequently, more fizz.