By Harold McGee
Fennel seed has the same anise-like aroma and sweet taste as the stalk and leaves of the plant that bears it, Foeniculum vulgare. Its dominant volatile is the phenolic compound anethole (see anise, above), supported by citrus, fresh, and pine notes. Most fennel seed comes from sweet fennel varieties and tastes sweet; seed from the less cultivated types are also bitter due to the presence of a particular terpene (fenchone). Fennel seed is a distinctive ingredient in Italian sausages and in Indian spice mixes, and in India is chewed as an after-meal breath freshener.