Take 250 g of black grapes in a pan, add 1 cup of water boil for 5 min. Stir occasionally.
Turn off the stove, squeeze lemon & cool it completely. Now the grape juice syrup is ready. This can be stored for 1 week by keeping it in refrigerator.
Now take a serving glass pour 1/2 cup of grape juice syrup, add ice cubes, sufficient water, pour some chopped grapes & serve.