I understand the draw of canned jellied cranberry sauce. It plops out of the can, has those pretty ridges, and can be sliced up and placed right in the center of a plateful of curly parsley. It's got a kind of Betty Crocker appeal to it. But whole-berry sauce-in-a-can-or-jar? Why do it?
Sure, we found some store-bought versions that were pretty good in our taste test, but homemade is so much better. Best of all, it's blindingly simple to make.
Here's why: First off, cranberries are extremely high in pectin. This is the cellular glue that holds plants together, and it's the primary gelling agent in jellies. Unlike most other berries used for jelly, which require you to add powdered or liquid pectin in specific quantities to get the requisite gel level, cranberries already contain the perfect amount. That means that all you've got to do is cook them down with some sugar and just a touch of water to get them started, and the cranberries basically do the work themselves, setting into a jelly all on their own.
Cranberries and cranberry sauce also have an extremely long shelf life. In part due to their high acidity, in part due to naturally high levels of antimicrobial phenolic compounds, fresh cranberries can last weeks (if not months) stored in the refrigerator. I make my Thanksgiving cranberry sauce at least a week ahead of time. It sits in the fridge, no problem, and saves me from having to think about it on Turkey Day.
Finally, making cranberry sauce yourself lets you adjust the flavorings any way you like 'em. I'm a purist at heart, so my sauce most often contains nothing but cranberries and sugar, but sometimes I'll add a couple of strips of orange zest and a splash of orange juice as it cooks down. Floral orange plays really nicely with the tart cranberries. A cinnamon stick can also be a good complement—the spicy phenolic compounds in cranberries are similar to those in cinnamon, so the flavors go quite well together.
Here are a few more ideas to get you started.