Francois Appert had no convenient tin can in which to seal his goods. He picked all sorts of food in glass of china containers, poured sufficient water to cover them, and then placed them in a bath of water which was gradually heated to the boiling point, keeping them in this bath for varying lengths of time. While still hot, they were corked and sealed. Perhaps, it may not seem like something that should be rewarded. It is done in many kitchens every autumn when the fresh fruits come in and are preserved for the winter. No, it’s not new or surprising now; it is the common and accepted one.
But, this is the twenty first century, and our French scientist was working in his laboratory in 1800. It is because Appert worked out this process so patiently and thoroughly in his workroom that we can do it so easily and naturally in our kitchens. The test took a long time, for different temperatures and methods had to be worked out. Then the jars must be left closed for months or years to prove the success or failure of each separate method. But by the time a dozen years passed and Appert had learned the best ways and was able to show many kinds of food which had been put away long before and yet came out as sweet and good as when they were placed in the jar.