Pluck ripe but firm grapes from the stalk, or place whole, large bunches in a jar. Pour on the following marinade: For 2 glasses water, use 1 glass of the best wine vinegar, and for every 3 glasses of liquid, add 2 glasses fine sugar and the zest from 1 lemon. Bring to a boil, stir, cool, and pour over the grapes. Place a round piece of wood on top, tie up with a bladder, and set on ice until the frost. Then store in a cold, dry basement where the grapes will not freeze.