Why Coke bottles developed an hourglass shape in the 20th Century
The reason for the "pinch in the middle" shape of the bottle had to do with making the contents of the bottle look like it was held more than it really did. By the late 20th century, that type of "false advertising" packaging was made illegal, but, well, Coca-Cola had been doing it for so long, most people never even realized that it was a trick.
In spite of whatever ingredients went into Coca-Cola, the most expensive was sugar. And around the time of World War I the price of sugar skyrocketed. So, putting a bit of a "pinch" on the sides of the bottle meant that you could give the illusion of the same amount of product (the bottle was about the same height) but with less content. Truth in packaging and labeling laws were still in the future!
The first people who saw the new bottle must have realized that the Coca-Cola was trying to cheat them, but we got used to it. Now it just looks kind'a cool.
Posted by Brad Hall