Make the Milk Mixture: Add the milk and vinegar to a small bowl, stir, and let sit for 5 to 10 minutes. (This is a substitute for buttermilk. See Notes)
In the same bowl, whisk in the mayonnaise. Set aside.
In a small bowl or blender, blend the peppers, pepper juice, and ½ of the milk mixture and vinegar.
Pour the blended mixture into the milk/mayo mixture and whisk.