Canning Bing Cherry Jam
24 Steps -- Step 12

Add a Pat of Butter and Bring to a Hard Boil

In our house margarine always changes into butter. You can use either one. We use margarine. The pat of butter/margarine greatly helps to hold down the foam when boiling the jam. Now apply high heat and bring the mixture to a full rolling boil. A full rolling boil is a boil you cannot stir down. During this time we are constantly stirring the pot with a long wooden spoon. We say long because you do not want a blob of boiling jam to land on your hand. Now while a "watched pot never boils" (false), a watched stirred pot doesn't stick or scorch.