By Harold McGee
Tarragon is the small, narrow leaf of a native of western and northern Asia, Artemisia dracunculus, a member of the lettuce family. The robust wild tarragon, often sold in plant nurseries as Russian tarragon, has a harsh and uninteresting flavor, while the relatively fragile cultivated form, “French” tarragon, has a distinctive aroma thanks to the presence of a phenolic compound called estragole (from the French name for the plant, estragon) in oil cavities alongside the leaf veins. Estragole is a close chemical relative of the anise aromatic anethole, and does have an anise-like character. Tarragon is a component of the French mix fines herbes, is the primary flavoring in béarnaise sauce, and is often used to flavor vinegars.