If you want to make the base with white grape juice, like Starbucks does, I recommend following the process I use in my Strawberry Acai Refresher recipe. Make the base with 2 ¼ cups white grape ...

Instead of making a fruit-based syrup (like I do for the Strawberry Acai Refresher ... and water in the base, you can make the drink with white grape juice instead. Starbucks does use white ...