Vanilla extract is the most prevalent form of vanilla in use today. Mexican, Tahitian, Indonesian and Bourbon vanilla are the major varieties. Bourbon vanilla is named for the period when the island of Réunion was ruled by the Bourbon kings of France; it does not contain Bourbon whiskey
Pure vanilla extract is a solution made by macerating and percolating vanilla beans in a solution of ethyl alcohol and water. In the United States, for a vanilla extract to be called pure, the FDA requires that the extract contain a minimum of 35% alcohol and 13.35 ounces of vanilla bean per gallon. Double and triple strength (up to 20-fold) vanilla extracts are also available.
Natural vanilla flavoring is derived from real vanilla beans with little to no alcohol. The maximum amount of alcohol that is usually present is only 2%-3%. Imitation vanilla extract, is a wood by-product typically made by soaking alcohol into wood which contains vanillin. The vanillin is then chemically treated to imitate the flavor of natural vanilla.