A candy maker helped popularize canning by bottling everything from eel to eggs to peaches

• In the 1800s, expanding empires and seafaring explorations required reliablely preserved food.
• A candy maker was awarded 12,000 francs for his method of heating and sealing food in glass jars.

In 1815, explorer and botanist Sir Joseph Banks wrote to a tinned-food manufacturer raving about the canned two-year-old veal he'd just eaten.

He called canned food "one of the most important discoveries of the age we lived in." He also requested a supply of concentrated consummé, as it was better than the soup he usually ate "at home or abroad."

At the time, commercial canned food was practically brand-new — nearly the same age as Bank's veal.

Finding a reliable means of preserving food was essential for colonizing and warring nations. That included Napoleon Bonaparte's France.

The search for food preservation methods

Napoleon witnessed the effects of hunger and thirst as he led his army through the Egyptian heat in 1798.

When he took power in France, Napoleon elevated doctors and scientists to positions of power to solve problems like this.

Those men then formed organizations and "supported research related to food preparation and preservation that might benefit France's armies and navies," historian Jennifer J. Davis wrote in "Defining Culinary Authority."

In 1809, one such organization, the Société d'encouragement pour l'industrie nationale, held a contest searching for food preservation methods.

Nicolas Appert — who had been sealing food in corked jars for several years and had already been experimenting with heating and bottling food for over a decade — took the prize.

The Appert method of food preservation

Appert had been in the food industry practically since childhood. His father was an innkeeper and brewery owner, and he'd worked in distilleries and wine cellars before opening his own confectionery shop.

The heating process needed to make candy as well as the bottling process for wine and beer may have influenced his method for preserving food. He described himself as reared "in the art of preparing and preserving" and "having lived, as it were, in pantries, in breweries, in store-rooms, and in the cellars of Champagne."

In 1795, he started trying to preserve different foods. He used empty Champagne bottles, then specially made glass containers. After sealing them, he'd boil the entire bottle and its contents in a water bath.

Appert wasn't precisely sure why his method worked, but he believed limiting its contact with air and the water's heat were "both indispensable." He was correct on both counts.

In addition to bottling vegetables and fruit like asparagus, cauliflower, peaches, and cherries, Appert also partially cooked some dishes before bottling and heating them. He made seasoned eel, mutton tongue, meat broth, and egg in bechamel sauce.

To make sure his food retained the proper color, aroma, and taste, he tested different times and temperatures for heating different dishes. Many probably wouldn't pass food-safety inspections, like the beef jelly that only needed heating for 15 minutes.

Each jar of preserves could cost a day's wage. For those who could afford it, they could open the can (which was actually quite a chore until the can opener was invented decades later) and enjoy almost-fresh green vegetables in the middle of winter.

Why Appert's method didn't catch on

In 1810, the French Ministry of the Interior paid Appert 12,000 francs to print a description of his preserving process "to spread the knowledge." His book, "The Art of Preserving Animal and Vegetable Substances For Several Years," sold thousands of copies.

"Appert has found a way to fix the seasons," according to one paper. Elite cookbook authors praised his process.

Folklorist Danille Elise Christensen noted that the "sugarless water-bath procedures" appeared in cookbooks written by women as early as the 1680s. Stories that focus on Appert while ignoring Mary Mott, Sarah Martin, and others "valorize 'scientific' over and against 'domestic' knowledge," Christensen wrote.

Appert had been able to scale his technique, at one point employing fifty cooks to help make his preserved dishes.

Other processes, including drying and using salt and sugar to preserve foods, endured after Appert published his book. His method was "not used widely on a scientific or industrial level" outside of his own factory, according to Davis.

Though the French navy had trialed Appert's preserves before he wrote his book, his fragile glass bottles weren't practical for sea voyages. Within a few years, another French citizen, Philippe de Girard, went to London and patented his idea for a tin can through an intermediary.

From glass bottles to tin cans

Bryan Donkin purchased the patent for £1,000, and it was he and his partners who made the consummé Banks so enjoyed. The cans could weigh as much as 20 pounds, but they were hardier than Appert's bottles.

The industry started spreading almost immediately. By the 1820s, the US had a few canneries, and the country's first patent for tin cans was granted in 1825.

This was all decades before Louis Pasteur developed his pasteurization method and realized bacteria caused contamination. His technique significantly reduced the number of bacteria without fully sterilizing the food — that is, killing off everything.

Botulism has been called "a disease of civilization." Sausages and smoked ham have both caused deadly outbreaks. Improperly canned food can also harbor the bacteria.

It's one of the many reasons commercially sold canned goods have waxed and waned in popularity in the centuries since Appert's first experiments.

Despite his early success, Appert struggled with debt. When late in life he was threatened with eviction, he wrote to the Ministry of the Interior, "I gave my life to science and to mankind. You're taking away the premises I thought ought to be mine."

Though he was evicted from his lab in 1824, the Restoration government eventually paid him 4,000 francs annually for ten years "in recognition of his service to the nation," according to Davis.