Tinplate is thin steel coated with a layer of tin, a soft silvery metal that resists rusting. This coating protects the steel underneath from moisture and air, which is why tinplate became the material of choice for food cans starting in the early 1800s.

Before tinplate cans, people preserved food by salting, smoking, or drying it. The invention of tinplate canning changed how we store and transport food. Soup, vegetables, fish, and other foods could suddenly travel long distances and last for months or even years without spoiling. Navies could sail longer voyages, armies could carry better provisions, and families could stock their pantries with food from distant places.

Despite its name, a “tin can” is mostly steel. The tin coating is extremely thin, just enough to help prevent rust. When you open a can of beans, you're using a technology that hasn't changed much in the past two centuries.