Essence is defined as possessing the qualities of something in concentrated form and extract is a solution (as in alcohol) of essential constituents of a complex material. So according to this, strictly the extract should be natural and the essence may be a chemical imitation. Like extracts, essences will keep indefinitely if stored in a cool dark place. Some further definitions...

• Flavour - A product that gives taste or enhances flavour in an existing product, other than flavour oils, essences and botanicals. It may contain water, propylene glycol, alcohol, etc.
• Extract - A flavour whose predominant solvent is alcohol.
• Emulsion - A flavour whose components have been dispersed and encapsulated in either a gum or starch suspension.
• W.O.N.F. - A natural flavour that has been enhanced with other natural flavours.
• Artificial - Denotes a product whose components are derived from synthetic process.
• Artificial and Natural - A blend that combines both synthetic and natural products by predominance. Also natural and artificial.
• Natural - A product in which all components come from natural sources. Also W.O.N.F.
• Spray Dried - A uniform encapsulated flavour system that offers extended shelf stability.