An opened Jar of store bought Jelly will last for up to 12 months or a year in the refrigerator.
As long as you keep the lid on the Jar of Jelly it will last a long time in the refrigerator.
When the Jelly starts showing mold in it or begins to change texture or smells bad then it should be thrown out.
When the Jar of Jelly is kept closed and not opened yet it can last for a few years even past expiration date.
Homemade Jelly will lasts for around a month in the refrigerator before it goes bad.
However you don't have to refrigerate the Jelly and it can be kept out at room temperature.
Jellies and jams do not need to go in the fridge because they have a water activity of around 0.80, and their pH is usually around 3.
So they don't have enough moisture to support bacteria and are too acidic for them as well. Conclusion: Keep your jams and jellies wherever you want to.
Properly stored, an unopened jar of jelly will generally stay at best quality for about 2 years.
Even if the Jar of Jelly has expired it does not mean the expired Jelly is bad.
Expired Jelly is safe to eat as long as it has no mold in it or it has actually gone bad.
Signs that Jelly has gone bad include.
Smell – If the jelly has gone bad, it may begin to smell a little bit strange.
Mold – This should be pretty obvious, but you should stay away from any jelly that has mold on the surface, or anywhere else for that matter.