Crush grapes with a wooden spoon in a porcelain or stainless steel kettle or use a fruit press if one is available. Add water and bring to a boil.
Press through a strainer twice. Return to kettle and stir in sugar until dissolved, bring almost to a boil (scald) and pour directly into sterilized bottles, then seal tightly.
Store in a cool dark place. If storing for a longer time, jars may be pasteurized at 190°F for 20 minutes, or in a boiling water bath for 10 minutes.
Note: Concord grapes are an excellent variety to use for homemade grape juice. The original recipe does not call for further processing to preserve fresh flavors and we have had good results in our trials. USDA methods recommend a brief pasteurization process.