The Ingenious Design of Crown Corks

The crinkled metal cap on glass bottles is known as a crown cork and features exactly 21 teeth. This specific number was chosen because it provides the perfect balance between a secure seal and easy removal.

Invented in 1892, the crown cork changed the beverage industry forever by providing a reliable way to keep carbonated drinks bubbly. The 21 ridges are designed to crimp perfectly against the glass rim, ensuring the seal remains airtight. Despite many new packaging innovations, this original design has stayed largely unchanged for over a century. It remains one of the most successful and cost-effective engineering solutions in history.