Changing up the type of vermouth called for in a manhattan is a time-honored way of producing amazing variations on a classic. The manhattan bianco is an excellent example of this technique, with floral blanc (or bianco) vermouth taking the place of the originals sweet vermouth. Its a major change in the flavor profile and, quite frankly, isnt much like a manhattan at all. But it is a genuinely lovely drink if you enjoy blanc vermouth. With bourbon, it leans sweeter; with rye, the bright pepper notes come through. Since there are no bitters, the lemon oil from the twist does a lot of work here, and we consider it an essential ingredient.