Photo: Tom (Flickr)
While it might be socially acceptable for food lovers to discuss the care of the finest wines, or the best way to brew gourmet coffee, what if your favorite beverage happens to be soda pop?
Chances are a gourmet wouldn’t have a lot to say about this topic. Well, don’t worry. It’s A Moment of Science to the rescue, as we take a practical approach to the chemistry of fizz.
What Is Soda?
Soda is fizzy because the gas carbon dioxide, or CO2, is dissolved into the sweet, syrupy liquid. Without this carbon dioxide your drink would be flat and unpleasant.
Unfortunately, carbon dioxide molecules have a natural tendency to leave any liquid, popping through the surface and escaping forever as a gas. The trick to preparing the perfect pop, therefore, is to keep as much of this dissolved CO2 inside the liquid as possible.
Why Do We Put Soda In The Fridge?
One way to do this is to refrigerate your soda as cold as possible, although you don’t want to freeze it. When soda is cold, the carbon dioxide molecules have less energy to escape, and cold soda can hold more CO2.
That’s why soda that you buy cold will be fizzier than soda that’s been sitting unrefrigerated on the store’s shelves.
Extra Carbon Dioxide
Another strategy, which the soda bottler might do at the factory, is to load up the air at the top of the container with extra carbon dioxide, or increase the pressure of this gas.
This will make it harder for the CO2 to escape, and also increase the rate at which these molecules are returned to the soda.