4 cups (2 lbs.) juice
7 cups (3 lbs.) sugar
½ bottle Certo
To prepare juice, stem about 3 pounds fully ripe grapes. Crush
thoroughly. Add ½ cup water, bring to a boil, cover, and simmer 10
minutes. Place in jelly bag and squeeze out juice. (Concord grapes give
best color and flavor. If Malagas or other tight-skinned grapes are
used, use 3½ cups grape juice, and add juice of 2 medium lemons.)
Measure sugar and juice into large saucepan and mix. Bring to a boil
over hottest fire and at once add Certo, stirring constantly. Then bring
to a _full rolling boil_ and boil hard ½ minute. Remove from fire, skim,
pour quickly. Paraffin at once. Makes about 10 glasses (6 fluid ounces
each).