Here is a ingredient that you might need to make, if you can't find it in stores.
Ingredients:
- 1kg green grapes
- Water. for washing (optional)
Method: Pick the green grapes off the stem, discarding any that are spoiled. The grapes should be sour enough to make you pull a face! Washing the grapes is optional. Puree the grapes in blender and take the resulting juice. It should be clear with a tinge of green.
I got this recipe from: www.food.com/recipe/make-you-own-verjuice-232609