It doesn’t. That’s what Coca-Cola’s spokespeople say, anyway. “The great taste of Coca-Cola is the same regardless of the package it comes in,” they insist. Rather, they say, “the particular way that people choose to enjoy their Coke can affect their perception of taste.” Sure, most people would agree that the cola is indeed delicious and refreshing, and pouring it into a glass or serving it over ice could influence the sensation of its flavor. But is it possible that the subtle variation in taste that some notice among aluminum cans, plastic bottles and glass bottles is more than just a psychological effect of their soda-consumption rituals?
Given that the formula is always the same, yes, according to Sara Risch, a food chemist and member of the Institute of Food Technologists. “While packaging and food companies work to prevent any interactions, they can occur,” she says. For example, the polymer that lines aluminum cans might absorb small amounts of soluble flavor from the soda. Conversely, acetaldehyde in plastic bottles might migrate into the soda. The FDA regulates this kind of potential chemical contact, but even minute, allowable amounts could alter flavor.
Your best bet for getting Coke’s pure, unaltered taste is to drink it from a glass bottle, the most inert material it’s served in. Even that’s not a sure bet, though. Coca-Cola maintains strict uniformity in processes in all of its worldwide bottling facilities, but it concedes that exposure to light and how long the product sits on store shelves may affect the taste. So yeah, the packaging might mess with Coke’s flavor, but we’ll still take it any day over New Coke.
Source
Popular Science
http://www.popsci.com/scitech/article/2009-07/why-does-coke-glass-bottle-plastic-bottle-and-aluminum-can-taste-different
