I buy jam and make jam. I've never had a jar of Smuckers or other store brand crystallize on me but I have had homemade jam crystallize in the fridge after a couple of months.
I buy two jelly products from a country store in Connecticut, raspbery rhubarb jam and red pepper jelly. Both of these will crystallize after bein open for a few weeks. I recently opened a jar of the red pepper jelly about 3 weeks ago and it's already crystallizing. Currently it's gone from the clear jelly look to an opaque color, crystallization is but a few days away.
I'm just wondering what it is about this stores products that makes them turn so quickly. And what is in Smuckers that prevents this from every happening?