If you ask the folks at Coca-Cola, it doesn't.
Technically, they say, it is all the exact same product. But come on -- you and I know that's just not true.
For starters, "Mexican Coke," which is Coca-Cola made with pure cane sugar instead of high-fructose corn syrup, is obviously extra refreshing. Ironically, only the Coke made in Mexico and then exported to the U.S. is made with sugar. The Coke made in Mexico and served in Mexico isn't.
But taste might actually have more to do with that glass bottle than previously thought. Sara Risch, a food chemist with the Institute of Food Technologists, told Popular Science that a material that lines the aluminum in cans of Coke could actually absorb some of the flavor from the soda. Meanwhile, a chemical from the plastic in the plastic bottles could actually make its way into the soda.
The best bet for a pure taste is to drink Coke from a glass bottle, says Risch -- though even that's not a guarantee. "While packaging and food companies work to prevent any interactions, they can occur," says Risch. And even things like exposure to light and time on the shelf can change the taste.
It's a pretty exact science. Like why the fountain drinks taste better at McDonald's: they're served colder, they syrup-to-water ratio accounts for melting ice, they make sure their water is extra-filtered and you drink it out of a slightly larger straw!