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Although there are people on the internet claiming canning is ancient, true canning is a product of the French Revolutionary Wars. Napoleon needed a better way to feed his army, so the French government offered 12,000 francs to anyone who could come up with a method to safely preserve food for their soldiers. Nicolas Appert, a chef, confectioner, and distiller, inspired by this call, spent 14 years trying to find a solution. He became the inventor of canning by putting food in glass bottles reinforced with wire, corking them, putting sealing wax over the corks, wrapping the jars in canvas, and then boiling the bottles.
Appert didn't really understand the science of why canning worked, but the French army trialed his canned food in about 1806, and in 1810 (some sources say 1809), Appert was awarded his 12,000 francs. Even before the French government gave their reward, however, Appert had made canning a commercial business. He was the first to use tin cans for this purpose, apparently soldering meat inside and then waiting months to see if the cans swelled. If they didn't, Appert considered the food inside safe. (Please note that we now know that is not an accurate way to ensure food won't cause illness.) In 1810, Appert published L’Art de conserver, pendant plusieurs années, toutes les substances animales et végétales (The Art of Preserving All Kinds of Animal and Vegetable Substances for Several Years). Now, others could follow in Appert's footsteps. In 1812, the first American commercial cannery opened.
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| A canning bottle like Appert used. (I've searched high and low for the origin of this photo. If it belongs to you, please let me know so I can give appropriate credit!) |
Mason jars were patented in 1858 and were designed to replace and exceed the cork and sealing wax some people were still using. Still, home canning wasn't a big thing; most people were still preserving food by smoking, drying, storing in fat, storing in salt, using cellars, etc. In fact, the inventor of the Mason jar, John Landis Mason, died penniless.
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| John Mason's original patent sketch. |
Then along came the five Ball brothers, who - after borrowing money from their uncle - purchased a commercial canning operation in the 1880s. In 1887, they moved to Muncie, Indiana, where natural gas was plentiful for glass blowing, and slowly, home canning started becoming more popular, with Ball leading the way by selling their jars to housewives.
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| An early Ball canning jar ad. |
The first pressure cooker was invented in 1679, but it was dangerous because it didn't have pressure release valves, which led the machine to explode. It took decades of tinkering by various people to make pressurized cooking remotely practical. In 1895, scientists from the Massachusetts Institute of
Technology (MIT) tried to figure out why canned clams got smelly and made the container they were in swell - still a common problem with meat and vegetables, even those that were commercially canned. Samuel Cate Prescott and William Lyman Underwood discovered that the microorganisms that caused the clams to do this could be killed by heating the cans up to 248 degrees F. This temperature could only be achieved by using pressure.
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| A 19th century commercial cannery. No date. |
By this time, scientists certainly didn't know everything we know today about microorganisms, but enough people had become ill from eating water bathed meats and veggies that it was well understood (even in laymen's literature, as my 19th century cookbook collection shows) that the only safe foods to water bath were fruits or pickles. Pressure canners allowed commercial canneries a leg up, as they made canned non-pickled vegetables and meats safer to eat. ("Safer" but not completely safe, because scientists still didn't understand that processing times needed to vary according to type of food, size of the can, etc.)
In the late 1800s, the U.S. Department of Agriculture (created in 1862) offered some recommendations on home canning fruit, fruit products, and pickles. In 1909, the first Ball canning book was published and was called The Correct Method of Preserving Fruit.
In 1905, the Presto company began making large, commercial-use pressure canners, and soon after, much smaller versions for home use. By the 1910s, fueled by the war effort and food rationing, many homes took advantage of pressure canning, as well as water bath canning. In 1917, the U.S. Department of Agriculture first stepped up to warm Americans that low acid foods could only be safely canned in a pressure canner - something non-government agency books from the 1800s had been saying for decades.
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| Cookbooks from the 19th century taught that only fruit and pickles were safe for water bath canning. |
Unfortunately, during the early years of the 20th century, a number of botulism poisoning outbreaks occurred. In 1919 and 1920, for example, there were outbreaks from commercially canned olives. Eighteen people died in New York, Ohio, and Michigan, and smaller outbreaks happened in other states. Commercial canneries, seeing their livelihood at risk, got together to try to improve the safety of canned goods. By 1925, these commercial canneries had set up stricter rules to keep harmful microorganisms, especially botulism toxin, at bay. The federal government soon began promoting these guidelines to home canners. By the 1930s, the USDA began doing some testing in home canning, possibly inspired by more outbreaks in botulism poisoning caused by improperly home canned food (especially the much publicized cases of the Zimmer family of North Dakota, who ate water bathed green beans, followed shortly by the Hein family and friends of North Dakota, who ate water bathed peas).
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| Botulism poisoning outbreaks in the early 1900s led commercial canneries to join together to discover the science behind making canning safe.
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Today, very little government testing in home canning takes place; what little is done is conducted by the Extension offices. However, the testing of home canned food (especially low acid foods) takes a great deal of time and resources that the Extension offices simply don't have funding for.
Ball continues to do some testing, too. In fact, it was their testing in the 1980s that led Ball to pull a fair number of their own canning recipes. Using new tools and knowledge, they learned that some of their recipes - pumpkin puree perhaps being the most famous - were not reliably safe. (In the case of pumpkin puree, this was because the density of the pumpkin could vary to such an extent that the food might not get heated through enough to kill harmful microorganisms.)
In addition, both Ball and the Extension offices review old testing periodically; rarely, recipes are pulled because the old data cannot be found. Once in a great while, a recipe is pulled because the old data combined with new knowledge shows that the recipe wasn't perfectly safe. (This happened just recently, with flower jelly recipes.) In addition, the USDA sometimes updates old standards based on new knowledge. An example of this was Ball adding acidity (like vinegar) to some of their newer recipes in order to improve the margins of safety, just this year.
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