I tried a hot pepper
jelly recipe from my Better Homes and Gardens cookbook. It canned fine,
but the jelly stayed runny in the jars. If I open the jars, is there
any way to re-process the jelly so it will set up, or am I stuck with a
batch of hot pepper soup?
If the jars are still sealed, you can check one of them now. Sometimes they set up a little more over time. Also, make sure that you check the consistency on one of them when they've been in refrigerator. They get firmer when cold and usually you'll be using it out of the fridge so that may be enough to do the trick when you're serving.
If they're still runny, you can just dump them in a pot and bring it to a slow boil. Then reduce the heat and cook slowly for maybe up to 4-5 more minutes and see what happens. Then re-seal into clean jars.