Updated: Jan 19, 2019
It all depends on how you care for your jam. I keep most of the jam in the freezer until we sell it, which for the most part makes time stand still. Once you open jam, I'd say it's good for 3 months if kept in the fridge. It is called "preservatives" after all. It's brought to a rolling boil for 5+ minutes (in Colorado that's what it takes to get it to set), which preserves the fruit.