Sugar and Salt

Sugar's role in home canning is more than making your preserves sweet.  It plays a critical role in making your jam jam.  That is without the right amount of sugar in a recipe, you'll have a running goo on your hands, not a firm, stable spread.  This is because of the chemical interaction that occurs when sugar and fruit pectin get together.  Pectin  is a complex carbohydrate.  When the pectin in whatever fruit you are using interacts with sugar, chemical bonds are formed that bolster the stability and smoothness of the mixture.  Sugar also serves as a natural preservative.  This happens because sugar is hygroscopic, meaning it pulls moisture out of the air.  In home canning, this is desirable, since any moisture that is drawn into the sugar molecules means less moisture available in the jar for microorganisms to invade and contaminate.  Whether you are using granulated sugar or sugar syrup made from fruit juice, be sure to use the proper amount indicated in the recipe to prevent mold brigade from feasting on your carefully crafted preserves before you do!

Salt is primarily used for flavor when canning vegetables.  It is essential to quality, texture, and safety when home-canning seafood, quick pickles and fermented foods.  Salt is made up of the chemicals chloride and sodium.  Like sugar, it is hygroscopic, pulling water out of the air and into itself.  Salt can however, be left out of the canned meat and vegetables.  Do not adjust the salt variety or amount in pickled product recipes.