Last year we harvested more Muscadine grapes then we could process at that time. Much went into jelly with the rest mixed with sugar and water as a concentrate then sealed in Ball Mason 12oz jars with heat. I'm guessing it's just considered grape juice concentrate at this point and if you add a jar of water or two it tastes just like grape juice. I have about a dozen 12oz jars that have just been sitting on a shelf. Would you give these a whirl and try to see if a batch of wine could be made from them? I was thinking I'd test each jar for pressure (if it hisses when opened) I'd be fairly comfortable the contents were preserved properly. Then I'd smell it and then give it a taste. If all was good I'd dump that in a primary with the others as I test them, get a good SG and see what happens. What would you do - try it or toss it?