White Soup with Garlic and Grapes (Ajo Blanco)

If you are using fresh almonds, boil them for 2-3 minutes. Drain and peel when they are cool enough, then grind them in the processor. If you are using ground almonds, put them straight in the processor with the bread, soaked in milk or water and squeezed dry, and the garlic. Blend to a smooth paste. While the blender is going add the olive oil, drop by drop, then in a slow stream, as with mayonnaise. Then add very cold water until the soup has a thick creamy consistency. Season with salt and vinegar, add the grapes and serve chilled.