Concord grapes. Sugar.
Pick over and wash sound grapes, rejecting all that are soft and bruised, but leaving a few of the stems. Put them into a preserving pan with a little cold water, but not enough to cover, and cook slowly until the skins break, stirring and mashing occasionally with a wooden spoon.
Boil for about two hours and then drain through a jelly bag. Do not press or squeeze or the juice will be cloudy.
Measure the juice, and to each quart allow one-half cupful of sugar. Reheat the juice to boiling point and cook for thirty minutes, removing the scum as it rises. Add the sugar, which has been heated in the oven, cook for five minutes, turn into hot sterilized bottles and seal airtight while hot.
If preferred, the grape juice may be canned without the addition of sugar, and glass jars may be used in place of the bottles.