How to make grape juice (Step by step recipe with photos): 1) Pick the grapes and take them into a large bowl. Fill it with water and let it soak for 5 minutes. Or rinse them under running cold water. 2) Then add the grapes to the blender. 3) Add sugar. You can skip the sugar if grapes are sweet enough.4) Add chilled water. 5) Blend it till it gets smooth. 6) Now strain it using the strainer. 7) Discard the waste. 8) add pinch of salt and stir. 9) Squeeze fresh lemon or lime juice. and mix.) Pick the grapes and take them into a large bowl. Fill it with water and let it soak for 5 minutes. Or rinse them under running cold water. 2) Then add the grapes to the blender. 3) Add sugar. You can skip the sugar if grapes are sweet enough. 4) Add chilled water. 5) Blend it till it gets smooth.