The citrus essential oils used in perfumery are extracted through the cold pressing of the citrus zests. The citrus peels (orange, lemon, grapefruit, bergamot, etc.) are first ground or chopped before being pressed. They then give a liquid mixture of essential oil and aqueous compounds which are finally separated. This extraction technique explains the volatility of the citrus notes in perfumery and the need to match them with the six other olfactory families.