Recipe for cooking grape juice

Recipes from Mexico :: Mexican Beverages

10 lbs. Concord grapes
2 quarts water
2 lbs. sugar

Use well-ripened but not overripe grapes. Pick over and wash grapes. Place in kettle. Cover with the water and let boil until the seeds are free. Strain while hot through a cloth bag. Heat juice to boiling point and skim. Let boil again and skim; then add sugar. Heat to the boiling point. Boil 1 minute. Pour into hot sterilized jars and seal, or use self-sealing bottles. If ordinary bottles are used, do not fill too full. Immediately after filling, place corks over bottles very lightly at first; as they cool, push corks down; then cover with melted paraffin or sealing wax to make the seal airtight. For white grape juice, select white Delaware or Tokay grapes.