Expressing Citrus Oils: the iceing on the cake

Expressing citrus oils over a cocktail is a finishing technique that impacts both aroma and flavor. When done correctly, it releases aromatic oils from the peel directly onto the drink's surface, which you smell immediately before taking your first sip.

Cut a piece of peel about the size of a quarter, with as little white pith as possible—the pith is bitter and you don't want it. Hold the peel between your thumb and forefinger, colored skin facing the drink, about three to four inches above the glass. Pinch sharply to bend the peel, which ruptures the oil glands in the skin and sprays a fine mist over the drink. You should see the mist if the lighting is right.

The oils float on the drink's surface because they're hydrophobic—they don't mix with water-based liquid. This creates an aromatic layer that hits your nose before the liquid hits your palate. For an Old Fashioned, orange oils add sweetness and warmth. For a Martini, lemon oils add brightness and cut through the spirit.

After expressing, run the peel around the rim of the glass to deposit additional oils, then either drop it in the drink or discard it depending on the cocktail. Some drinks benefit from the peel steeping in the liquid; others don't.

Common mistakes include not pinching hard enough, holding the peel too far away so oils disperse into the air instead of landing on the drink, or using peel with too much pith attached.

Get this right and your cocktails will smell noticeably better before anyone takes a sip. It's a small detail that makes a significant difference.