Reader Dan asked the following question: can someone explain the jars in a waterbath stage? ive never heard of this and i make a lot of jams
Technically any recipe that is canned needs to be heated either by waterbath or pressure canning. This is to heat what is inside the jar and kill and bacteria. I admit to occasionally using what is called the open kettle method meaning I do not process the jars at all. I should point out that this method is unsafe and should never be used.
Waterbath and pressure canning are very different. Only fruit or jams should be waterbath canned. Meats and vegetables should be pressure canned. You can read more about the differences here. Waterbath canning involves completely submerging the jars in a pot of boiling water for a set amount of time.
While I like to live on the edge, I have started waterbath canning my jams/jellies. The main reason is that I now use a low sugar pectin. Sugar can help prevent bacteria growth. Using less sugar in a recipe means there is a greater chance of bacteria growth. It is simple to do, and I figure it is just an added precaution.