They are made the same way except that cranberry jam has a lot more sugar added so it is sweeter and may contain extra ingredients such as spices (cinnamon, nutmeg, cloves, allspice) or orange juice or rind/zest. Cranberry sauce is usually more savory and thicker and has a lot less sugar added and is generally served with meat. Cranberry preserve is sweeter and can be used as a topping on almost any breakfast you may think of.