You may not realize it, but the humble cans of soup gathering dust in your pantry helped revolutionize the world. And believe it or not, canned food started out as a weapon of war.

Canning was invented in 1809 by Nicolas Appert in response to a request from the French military to create a method of preserving food for a long time. Large armies need a lot of food, especially if deployed for long periods of time. And if armies operate far from their home territory, securing supplies and food, in particular, can be difficult. Canning has made it much easier to preserve food. This, in turn, made it easier to supply armies, explorers and others who had to rely on canned foods.

Although Appert invented the canning process, he didn’t really understand why it worked. It will take another half century for Louis Pasteur to unravel the mysteries of canning. When food is canned, it is placed in a can or similar container, such as a glass jar. The container is then sealed, preventing outside organisms from entering. Then the canned food is heated to kill any germs still alive inside. Pasteur was the first to prove that microbes cause food to spoil.

Ultimately, canned foods made it easier for explorers to travel the American West and cross oceans around the world. For better or worse, canned foods made it easier to deploy large armies for longer periods of time. This may have made the American Civil War and the Crimean War in Europe, among other conflicts, bloodier as armies were able to march farther and stay in the field longer.

In the early 1900s, food canning was a popular household technology, adopted by women around the world after the invention of new resealable jars by Charles Ball and Alexander Kerr.
Canned foods also help make food in general cheaper. Until the 20th century, food took up a much larger share of the average family budget.