Squeeze pulp from grape halves into a bowl, reserving skins.
Bring skins to a boil in a large sauce-pan over medium-high heat. Cover, reduce heat to medium, and cook, stirring occasionally, 15 minutes or until tender.
Bring pulp to a boil in a saucepan; reduce heat to medium, and cook 20 minutes or until seeds separate from pulp. Pour mixture through a wire-mesh strainer into saucepan containing skins, discarding solids. Add sugar, and cook, stirring occasionally, over medium heat, 2 hours or until thickened. Stir in vinegar and next 3 ingredients. Cook 10 to 15 minutes or until a candy thermometer registers 225° to 230°.
Ladle hot mixture into hot, sterilized pint-size jars, filling to 1/2 inch from top. Remove air bubbles; wipe jar rims. Cover at once with metal lids, and screw on bands.
Process in boiling-water bath 20 minutes. Serve with turkey, biscuits, or toast.
*5 pounds of seedless red grapes may be substituted. Crush whole grapes slightly. Bring to a boil; reduce heat, and simmer 20 minutes. Strain mixture into a saucepan, discarding solids. Stir in sugar, and proceed as directed.