Adapted from New Food for Life: Ancient Persian and Modern Iranian Cooking and Ceremonies, by Najmieh Batmanglij (Mage Publishers).
• 12 pounds unripe grapes
• 1 tablespoon salt
Wash the grapes and remove the stems. Drain and pat dry. Extract the juice by grinding the grapes in a blender, food processor, or juicer. If you use a blender or food processor, pass the pulp through a fine or medium-fine sieve. I don't mind if the juice has some pulp.
Pour into a non-reactive pan, add the salt, and bring to a boil, stirring often. Cook only one minute and remove from the heat. Pour into sterilized bottles, seal them (boiling in a water bath, if you like), and keep in a cool and dark place.
To read Aglaia's article about what to do with unripe grapes—and the history of verjuice—click here.