Bottle Cap: The Secret of 21 RidgesThe mathematical reason your drink is sealed with an odd number

From the show

Why it looks like that

The "crown cork" revolutionized bottling by creating a perfect seal for carbonated drinks. Originally designed with 24 ridges, manufacturers discovered this even number caused caps to interlock and jam inside automated feeder tubes. The shift to exactly 21 ridges uses an odd number to prevent nesting, ensuring high-speed production lines never stop moving while maintaining consistent pressure.