In 1795, the French Directory offered a 12,000-franc prize for any method that could preserve food well enough to keep Napoleon's armies fed on long campaigns. A Parisian confectioner named Nicolas Appert spent fourteen years tinkering in his kitchen and won it. His 1812 manual — translated from the second London edition — was, as its title page declares, "A WORK PUBLISHED BY ORDER OF THE FRENCH MINISTER OF THE INTERIOR, ON THE REPORT OF THE BOARD OF ARTS AND MANUFACTURES."

The table of contents reads like a culinary moonshot. Appert claimed he could preserve, for years:

Boiled Meat... Gravy... Broth, or Jelly... Round of Beef, Fillet of Mutton, Fowls, and young Partridges... New-laid eggs... Milk... Cream... Whey... Green Peas... Asparagus... Windsor Beans... Artichokes... Cauliflowers... Sorrel... Spinage... Love-Apples [tomatoes]... Cherries, Raspberries, Mulberries...

His method, distilled across sections on "Bottles and Vessels," "Corks," "Corking," and the long parade of foodstuffs, was deceptively simple: pack food into thick glass bottles, cork them tightly, wire the corks down, and submerge the bottles in boiling water for varying lengths of time. That's it. That's modern canning.

Here is the astonishing part: Appert had no idea why it worked. Louis Pasteur would not propose germ theory for another half-century. Appert was operating in the era of "miasmas" and humors. He believed, vaguely, that heat drove out some kind of vitiating principle and that air was the enemy — a hypothesis that happened to be correct enough to feed armies, sailors, and eventually astronauts.

His instincts were uncanny. The book includes preservation of milk and cream — a feat that would not be industrially repeated until Borden's condensed milk patent of 1856. It includes whey, eggs, and the juices of medicinal herbs. He understood that different foods required different boiling times, the foundational insight behind every USDA canning chart in your grandmother's kitchen.

Within a decade of his book's publication, Englishman Peter Durand patented the tin can (Appert had stuck with glass, which shattered on horse-drawn supply wagons). The British Navy adopted canned rations. By 1820, sailors on Arctic expeditions were eating Appert-method food. By 1928 — when Della Lutes was writing The Presto Book of Menus and Recipes about home canning — Appert's hot-water-bath method had become so normalized that American housewives performed it every August without a thought to its inventor.

The next time you open a can of tomatoes, you are participating in a technology whose mechanism was a complete mystery to its inventor for the rest of his life. Appert died in 1841 — eighteen years before Pasteur published on fermentation — believing he had figured out something about air. He had actually figured out something about microorganisms he could not see and did not know existed.