Coca-Cola DEFINITELY develops an odd taste often around 5-6 months BEFORE it's sell-by date. A kind of bitter-metallic taste is the best I can describe it. I usually check the sell-by dates, but sometimes I forget. It's important to check, especially if you're buying 1 or 2 liter bottles in convenience stores, as they tend not to sell as many as a larger grocery store and are on the shelves much longer. A few days ago I bought a 6 pack of 8 ounce glass bottles (the best way to drink Coke!) with a sell by date of March 2026, 7 months from now. Half of them already developed the funny taste! And I know it's not just my old taste buds, I've been drinking Coke for 45 years and I noticed it a long time ago