Concords or some of the dark purple grapes are the richest and most satisfactory for juice. Pick the grapes from the stems, wash and drain, put into a preserving kettle without water, cover and put on back of stove on an asbestos pad or a ring so they will heat slowly. When the skins are broken and the juice is free, bring just to the boiling point, put into jelly bags and drain without squeezing. To each quart of juice add from 1/2 to 1 cup of sugar. Very ripe grapes will require no sugar. Heat to boiling and can the same as fruit.