Happy 220th Birthday to the Can

canned-veggiesFood preservation is as old as agriculture. For millennia, that consisted of smoking, salting, drying and, eventually, sugaring. Strangely enough, the next major advance in food preservation was developed in pursuit of military conquest.

Napoleon Bonaparte’s place in history is secured because of his political and military achievements. Less well-known, but probably as important, is his role in the development of canning. He knew that brilliant military strategies were worth little if his troops couldn’t eat well enough to keep healthy and strong for battle. In those days, armies in foreign lands mostly lived off whatever food they could steal, pillage, forage or buy – a strategy that crippled countless military campaigns. In 1795, Napoleon offered a 12,000 franc reward (a fortune in those days) to anyone who could develop a method of preserving large quantities of food.

A French brewer and confectioner, Nicholas Appert, collected the prize, having observed that food cooked inside a glass jar didn’t spoil unless its seal leaked. He developed a method for sealing without ever knowing why it was necessary: it would be another half-century before Louis Pasteur discovered the role of microbes in food spoilage.

The only problem with glass was breakability, especially when transported in rough-and-ready military conditions. Soon glass was replaced by cylindrical wrought-iron canisters (soon shortened to “cans”), sometimes lined with tin. It was an expensive and time-consuming process. Each can had to be wrought by hand. They were large, and cooking the contents took as much as six hours. Can openers had yet to be invented; soldiers opened those first canned foods by piercing them with bayonets or smashing them against rocks.

For several decades, canned food remained the province of armies and navies in France as well as other European countries. They were also utilized by explorers of the era. A can of food left by the British Sir John Franklin in the Arctic in 1845 was discovered in 1857 and opened in 1939 and found to still be edible. However, no record was made of the amount of lead it contained. Lead solder was used to seal early canned foods and undoubtedly resulted in cases of lead poisoning.

Canned food remained a novelty, one usually only fairly well-to-do folks could afford. But an expanding and prosperous urban middle class – and the widespread use of canned food in wars from the Crimean to the American Civil War – made the manufacture of canned food a growth industry, helped by a number of innovations and inventions.

Still, canned food remained out of the reach of farm families and those too poor to be able to buy it. That changed in 1858 when a New York tinsmith, John L. Mason, invented a glass jar that had a threaded lip and reusable metal lid. The Mason jar was born, and it revolutionized food preservation in America and Europe.

Home canning was widespread by 1900, but was mostly restricted to high-acid foods such as tomatoes. Methods for low-acid foods would come later with hot water bath or pressure canning. Most home canners of the time used what is called the “open kettle method,” in which boiling jam or brine would be poured over a hot, sterilized jar until it almost overflowed. The object was to kill the bacteria on both the inside of the jar as well as the lip.

The Victory Gardens of two World Wars and the Great Depression in between resulted in ever-increasing numbers of home canners. Some towns even set up their own community-run canning centers, with instructors, equipment and supplies so people could work together to can large amounts.

In the 1950s, Clarence Birdseye developed methods and equipment for freezing food for home cooks. It didn’t take long for home food preservationists to begin utilizing freezing instead of or in addition to canning.

In the ’60s and ’70s, home food preservation began to decline. The availability of cheap commercial canned and frozen food, increasing urbanization, and women working outside the home were among the factors. By the end of the 20th century it seemed as though home preservation was going the way of the dodo.

But these days, home preservation is enjoying a renaissance. Home extension services give classes that are quickly filled and have waiting lists. Sale of home canning equipment went up almost 12 percent. Part of home preservation’s resurgence is due to the economy. The other major factor, though, is that more and more people want to know where the food they eat comes from, how it’s handled and how it’s processed. And there’s no better way to be sure of that than by doing it yourself.

For instructions on canning, check out Atlanta’s Blake Slemmer blog on home canning written in everyday language.