What is the main alcohol used in a Rusty Nail cocktail?

The Rusty Nail cocktail is primarily made with Scotch whisky, which serves as its base spirit. This classic cocktail is a combination of Scotch and Drambuie, a sweet, herbal liqueur that enhances the flavors and adds complexity to the drink. The choice of Scotch is essential because it brings a distinct smoky and rich character that is fundamental to the Rusty Nail's profile. The balance between the robust qualities of the Scotch and the sweetness of the Drambuie creates a unique flavor experience that is signature to this particular cocktail.

Other spirits, such as vodka, rum, or gin, may create different cocktails entirely and would not deliver the same taste or experience that the Rusty Nail is known for. Thus, Scotch is the only spirit that aligns with the traditional recipe of this drink.