Today I wanted to add to the fun facts about canning history with this topic. Why are mason jars made of glass? You may not have ever thought about it but sometimes odd questions like that come to me and I wonder why are mason jars not made out of clay like pottery or crocks? I also find it amazing that since canning was invented we still use the same basic design of glass jar. The only thing that has really changed about them is the method of sealing. As I mentioned in a previous post, Nicolas Appert was the inventor of heat processing food preservation that he developed by placing cooked food in glass jars, removing as much air as possible and sealing the jars with corks that were wired in place then processed in a water bath. He used glass because he believed that it was air that caused food spoilage and glass is not easily penetrated by air. I also briefly documented the story of the inventor of the mason jar here. Even though it wasn't known at...