How to Make It
In a food processor, pulse the almonds until finely chopped. Transfer to a large bowl and add the water. Mix well, cover and refrigerate overnight.
Working in 2 batches, puree the almonds with their soaking liquid in a blender until smooth. Strain the almond puree through a fine sieve, pressing on the solids. Discard the solids. You should have about 6 cups of almond milk. (If you don’t have enough, add cold water to make 6 cups.)
In a blender, combine 3 cups of the almond milk with 1/2 cup of the bread cubes, 1 garlic clove, 1 tablespoon of the vinegar and 1 teaspoon of the salt. Puree until smooth. With the machine on, slowly drizzle in half of the oil. Transfer the soup to the large bowl. Repeat with the remaining almond milk, bread, garlic, vinegar, salt and olive oil. Strain the soup through a fine sieve into another large bowl, pressing gently on the solids. Cover and refrigerate until very cold, about 4 hours.
Season the soup with salt and vinegar. Spoon the crab and grapes into 6 bowls, add the soup and serve.
Making almond milk is supersimple, and crucial for this recipe. Be sure to use skin-on raw alonds for the most flavor.