For years, both my mother's and my own apricot and peach jams would never set up. The pectin package warned us that it might take up to 2 weeks to set (WHY??), and we always waited and checked, but it didn't happen then either. Plum and blackberry jams always came out perfect every time.
Other acquaintances in the area (SF bay area) reported the same thing. I think I have a fix - just put in more lemon juice, like double (or even more), what the recipe calls for. This has worked well for me a few batches now, but my question is why?
Why would the pectin company put a recipe in their box which doesn't work for so many people? Are we all doing something wrong? Or is there something about California fruit - or California lemons? - that is different from the place these recipes were written for? ... Or something about our atmosphere?? And why do these recipes mention that apricot/peach, specifically, might take up to 2 weeks to set.