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 that once food was away from air it would keep it from spoiling. 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. Food treated this way will keep for years and will be ready to eat when opened. A more modern way of canning is the "tin canister" or now known as the "can". The tin can makes preserving food simpler. There is no need for pickling, salting, drying or smoking the food. Although this method is usually used in the manufacturing of sellable foods, home methods are still used today. There are only two universally accepted, methods for home canning: boiling-water bath, and pressure canning. In both of these a canning jar and airtight seal are needed. During process!
             ing the food and jars reach 212' F to 240' F. 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. As the food cools, it contracts, creating a vacuum. The lid is sucked down tight preventing air from passing in or out of the jar. With proper storage, the seal will remain tight.
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