Why does freezing soda make it go flat?
In: Chemistry
I’ve accidentally frozen soda before, and it wasn’t flat after it thawed. Care to elaborate how you’ve seen this happen?
The soda is carbonated in the first place because it has CO2 gas dissolved in it, basically meaning that there are CO2 molecules mixed in with and interacting with the water molecules of the soda. While I couldn’t find much information about this online when I looked for it, I’m fairly certain that the soda losses it’s carbonation because ice is much worse at dissolving CO2 than water is. Imagine it like this, when water is liquid you have a bunch of molecules moving around and sliding past each other and it’s pretty easy to squeeze some gas molecules in there too, but when water freezes, all of its molecules hold mostly still and align themselves into a crystal with very little room for other things in it. Hope that helps!
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.
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