It all started back when the Japanese bombed Pearl Harbor…
…or so quite a lot of people seem to think. World War II may have been the historical high water mark for home canning, but preserving the harvest in jars is a tradition that goes quite a bit further back. As I mentioned, it was Nicholas Appert who invented canning for Napoleon in 1809. That, however was by no means the beginning of home canning. For a considerable time thereafter, canning was tantamount to a top secret military technology, created to feed the gigantic armies that the innovations of national conscription and industrial weapons production had made possible.
Indeed early canning was irrelevant to average folks, who went on preserving their harvests in traditional ways: drying, salting, brining and sugaring (if they could afford the sugar, that is). Meats were sometimes “potted”, i.e. cooked and immersed in fat to keep the air out (what the French refer to as a confit).
By the mid-1800’s canning was fairly widespread as a commercial industry, yet for average middle class people, canned food was little more than an expensive novelty. The technology of the day was a far cry from what we know now. Cans were heavy, stoppered with cork and often sealed with lead, which, as any member of the Franklin Expedition would have told you, was downright hazardous to your health. The interesting thing about canning in those days was that nobody knew how it actually worked. Sure people understood that in order to preserve food it was essential to keep air away from it, but they didn’t know why. No one had any concept of microbes then (Louis Pasteur had yet to undertake his groundbreaking research), and most people ascribed food spoilage to the theory of spontaneous generation (for more on that, see the post Sweaty Undershirts + Hay = Mice).
It wasn’t until about the time of the Civil War (the 1860’s) that true home canning came into being. The reason, because a tin smith from New York by the name of John L. Mason invented a glass jar with a threaded lip and a reusable metal lid: the Mason Jar. This miracle invention allowed people all over America (and Europe) to engage in the canning of fruit, pickles, relishes and sauces like ketchup. Widespread canning of low-acid vegetables and meat would come later, for it was still too dangerous.
The 1880’s saw two major developments in home canning: the all-glass (hence rust-proof) clamp-top “lightning” jar and the widespread adoption of the cast iron stove. These two developments, which happened to dovetail with a significant drop in the price of refined white sugar, led to a veritable explosion in the popularity of home jam making and canning.
Interestingly, it was mostly the wealthier residents of small towns and/or suburban dwellers who engaged in the canning arts. Farmers of the day, being quite poor as a rule, usually bartered with one another for what they needed day-to-day. Sure they had the produce, but cash, which was what was needed to buy the rather expensive jars, was usually in very short supply. Urbanites had the opposite problem: plenty of cash but no fresh produce. Thus suburbanites or small-town tradesmen and business people were the ones in the proverbial cat-bird seat.
Here it’s important to note that as widespread as canning was by about 1900, it wasn’t practiced as it is now. Home canners employed what we now call the “open kettle method” in which boiling jam (or brine in the case of pickles or relish) would be poured over a steaming hot jar to the point of overflowing. This had the effect of killing bacteria both inside the jar and on the lip. A lid, which itself was kept in simmering water, would then be popped on the top. The combined heat of the lid, jar and its contents was usually enough to kill off any critters in the air gap between the jam and the lid. It was a decent enough method, though not nearly good enough for non-acidic vegetables and meats, which unlike acidic and/or sweet preserves, can grow anaerobic botulinum bacteria if not heated thoroughly. Those types of foods would have to await the advent of the pressure canner.
Even so, home canning was well established in America well before even Word War I broke out, the time Americans first began planting “Victory Gardens” and canning their harvest to to the pressure off essential industries. People did the same in World War II of course, some towns even had their own community-run canning centers, which provided the equipment, supplies and expertise that allowed people to can mass quantities of food safely and efficiently.
Alas, those days were pretty much the end of home canning in America. As supermarkets proliferated and industrial goods got better (and cheaper), most people decided it wasn’t worth the time and effort to can their own food. Only a few very determined sticks-in-the-mud persevered.