Submerge bread in cold water, set aside 10 minutes, then drain and squeeze out excess liquid.
Purée Chobani, ice water, almonds and salt in a blender on high. Add garlic and purée again. Add 2¼ c grapes and soaked bread and blend until smooth.
With blender running slowly add olive oil and blend until smooth, then strain through a fine-mesh sieve.
Stir in the sherry vinegar and serve in bowls with olive oil, extra grapes and a lemon wedge.