Concord-type grapes grow well here in the far north, and if we don't get early frost and can protect them from the critters, we have heavy harvests. A friend gave me this recipe for grape juice, and it's got to be the easiest canning recipe ever. We put up loads of it every year. Use all the basic proper canning techniques, of course.
In each sterilized quart jar, put 1½ to 2 cups cleaned grapes. Add 1/4 cup sugar, more or less, depending on sweetness of grapes and your tastes. I lean toward less sugar for the grapes we grow. Squash the grapes just a little with a big spoon. Fill to the top with boiling water, leaving ½" headspace. Process 10 minutes in a water bath canner.
THAT’S IT! THAT’S THE WHOLE THING! Let the jars sit for at least 2 weeks before drinking any juice. The longer it sits, the stronger it becomes; you may wish to dilute it with water or sparkling water. Strain the juice through an ordinary screen strainer before drinking. Chill and enjoy. If you didn't put in quite enough sugar to suit your tastes, add a little apple or other juice to sweeten.
