It's easy to not think about the fact that juice companies can somehow make juice that tastes the same all year. Sadly, it's heavily processed and then re-flavored. Even the brands that are advertised as "natural", aren't. Still, it's interesting to see a little of how this happens, if also a bit sad.
After the oranges are squeezed, the juice is stored in giant holding tanks and, critically, the oxygen is removed from them. That essentially allows the liquid to keep (for up to a year) without spoiling — but that liquid that we think of as orange juice tastes nothing like the Tropicana OJ that comes out of the carton. In fact, it's quite flavorless. So, the industry uses "flavor packs" to re-flavor the de-oxygenated orange juice... Juice companies therefore hire flavor and fragrance companies, the same ones that formulate perfumes for Dior and Calvin Klein, to engineer flavor packs to add back to the juice to make it taste fresh. Flavor packs aren't listed as an ingredient on the label because technically they are derived from orange essence and oil. Yet those in the industry will tell you that the flavor packs, whether made for reconstituted or pasteurized orange juice, resemble nothing found in nature. The packs added to juice earmarked for the North American market tend to contain high amounts of ethyl butyrate, a chemical in the fragrance of fresh squeezed orange juice that, juice companies have discovered, Americans favor... Since they're made from by-products that originated in oranges, they can be added to the orange juice without being considered an "ingredient," despite the fact that they are chemically altered.