Whiskey serves as the base spirit of the Old Fashioned. Typically, bourbon or rye whiskey is used, each bringing its distinct flavor profile to the cocktail. Bourbon offers a sweeter and smoother taste, while rye whiskey has a spicier and more robust character.

Angostura bitters are a key component of the Old Fashioned. Bitters are concentrated herbal extracts that add depth, complexity, and a hint of bitterness to the cocktail. A few dashes of Angostura bitters are essential to achieving the Old Fashioned's signature flavor.

In some recipes, a splash of water is added to help dissolve the sugar and bitters more evenly. This can be done by muddling the sugar cube with a few drops of water before adding the other ingredients.

Traditional Old Fashioned recipes call for a sugar cube. However, simple syrup (a mixture of equal parts water and sugar) has become a popular alternative. The sugar cube or syrup adds sweetness and helps to mellow out the intensity of the whiskey.

An orange peel is often used as a garnish for the Old Fashioned. Expressing the oils from the orange peel over the cocktail's surface releases an aromatic burst that enhances the drinking experience.

Some variations of the Old Fashioned use a lemon twist as a garnish instead of or in addition to the orange peel. The lemon twist can add a brighter citrus aroma.