Since the beginning of time, people have looked for ways to preserve food for future use. There are no records around telling when the first preservation method was discovered or used. Perhaps people noticed that a fire dried food and that the smoke preserved it. Or maybe hungry hunters ate dried berries on a bush and realized that they liked the taste. By chance, people could have left food in the snow and once retrieved, found that the frozen food lasted longer than the fresh. In these ways, people might have learned how to protect foods against the effects of time.
Out of all the methods of preservation canning is the one that is still used most often. The method started when Nicholas Appert, a French Candy maker won a prize when he made a sealed, glass container. He realized th
In both of these a canning jar and airtight seal are needed. A more modern way of canning is the "tin canister" or now known as the "can". Food treated this way will keep for years and will be ready to eat when opened. The lid is sucked down tight preventing air from passing in or out of the jar. Once tightly sealed the food needs to be kept in a cold, damp place. at once food was away from air you could keep it from spoiling. A hundred years ago root cellars were one of the few ways they had of keeping things cool. Appert's process of heating pre-cooked food in a container and sealing it tightly killed all the bacteria in the food and kept out air. Many have doors swinging open from the top but more modern ones are only covered on 3 sides by the earth. As the food cools, it contracts, creating a vacuum. Air remaining in the food and in the space at the top of the jar is forced out between the jar and lid. As the jars cool, they automatically form a tight seal. Even though root cellars didn't get nearly as cold as a refrigerator during summer months, root cellars generally were and are 30 to 40 degrees F. There is no need for pickling, salting, drying or smoking the food. The root cellar, which is excellent for this purpose is still used today.