What ingredient is used to sweeten an Old Fashion cocktail?

The Old Fashioned cocktail traditionally uses sugar as its sweetening ingredient. This classic cocktail is known for its simplicity, and the sweetness from sugar helps to balance the bitterness of the aromatic bitters as well as the strong flavor of the whiskey or bourbon used as the base spirit.

Typically, sugar is often served in the form of a sugar cube, which is muddled with bitters and a splash of water or soda to dissolve it before adding the whiskey. This method not only adds sweetness but also contributes to the drink's texture and mouthfeel.

While syrup, agave nectar, and honey are all common sweetening agents in various cocktails, they deviate from the traditional recipe of an Old Fashioned. The use of syrup would imply a different preparation style, agave nectar is usually associated with tequila-based drinks, and honey offers a distinct flavor that may overwhelm the fundamental characteristics of the Old Fashioned. Thus, sugar remains the quintessential sweetener for this classic cocktail.