Clean the grapes.Put all the grapes in a pan on fire. Add little water to it. Boil this until the grapes completely dissolves in the solution (around 15 minutes). Smash it with a ladle. Strain the juice using a big strainer and cloth. Keep aside.
Heat the 1 cup water and add sugar and citric acid to it. When the sugar completely dissolves, remove from the fire and sieve through a thin cloth. Allow it to cool.
Add the grape juice and essence to this syrup and stir well. Store the squash in a bottle.
To serve, take 1/4 glass of squash and mix it with water.