Butterscotch can refer to the natural flavor produced from the heating of dark sugar and its mixing with cream, or pale imitations thereof. Some of the tastes of natural caramel and butterscotch come from pyrolytic caramelization. Other components of the flavor come from the reactions of sugars and milk proteins in the Maillard reaction.
While some recipes call for adding Scotch whisky to the preparation, the "scotch" in the name actually comes from an old suffix "scotch" meaning "to cut". "When sugar or candy is hot it's difficult to get a clean break, so one must score it while warm to facilitate getting a clean edge later." This etymology, however, does not preclude the addition of whisky or rum to a butterscotch preparation.
- Shuna Lydon (27 March 2008), "How to Make Butterscotch", Simply Recipes