Why does freezing soda make it go flat?
In: Chemistry
Fundamentally its because when something freezes, impurities generally don’t freeze into the main body; though this partly depends how quickly its frozen, and the nature of the impurities.
Fizzy drinks are made by forcing an extraordinary amount of carbon dioxide to dissolve into the water under pressure, so even under normal conditions once they’re opened this gas gradually escapes again.
The process of freezing something causes the molecules of the substance to arrange themselves into a regular lattice structure as it solidifies. But different substances freeze at different temperatures, so as the water of the drink freezes, the carbon dioxide is going to remain gaseous unless you’ve brought the whole lot down below -79°C extremely quickly. So while the water molecules are collecting together into lattices, the carbon dioxide molecules are still moving around quite quickly and freely.
EDIT: I should say that this is when you freeze once the drink is open. If the bottle is still sealed then the pressure might still mean it can keep the fizz after defrosting.
Latest Answers