The Rob Roy is a cocktail made up of Scotch whisky, sweet vermouth (or dry vermouth) and bitters. Today's version of the Rob Roy is made with sweet version, made with sweet vermouth, so there is no need to specify a ‘sweet’ Rob Roy when ordering, however… many people prefer a ‘dry’. In this case the Rob Roy is made by substituting dry vermouth for the sweet vermouth. A ‘perfect’ Rob Roy is made with equal parts sweet and dry vermouth.
The drink was named in honor of the premiere of an operetta, popular at the time, called…Rob Roy, loosely based upon Scottish folk hero Robert Roy MacGregor. The Rob Roy is similar to a Manhattan but is made exclusively with Scotch whisky, while the Manhattan is traditionally made with rye and today commonly made with bourbon or Canadian whisky. Like the Manhattan, the Rob Roy can be made sweet, dry, or perfect. The Rob Roy is usually served in a cocktail glass and garnished with a cherry (for the sweet version) and a lemon twist (for the perfect and dry versions). Cheers!