Don't get out the ruler and measure, but eyeball the headspace. If you don't, it'll boil over the seal or explode. I just boiled over my seals (yeah, another point - be sure the tops are screwed on TIGHT!) when I did spicy dilly beans a couple weeks ago...
Did you follow a recipe from the beginning? As you add pectin, you'll also need to add sugar... I try not to use pectin of I can help it.
Ah hah...that makes sense. Not exploding would be a good reason.
Sorry about your peaches and spicy dilly beans. Were you able to salvage them?
I did follow the recipe, I did not know I should have added more sugar!
I dont even know what to do at this point.