Vanilla extract is a solution containing the flavour compound vanillin. Pure vanilla extract is made by extracting from vanilla beans in an alcoholic solution. In order for a vanilla extract to be called pure, it is required that the solution contain a minimum of 35% alcohol and 13.35 ounces of vanilla bean per gallon. Double and triple strength vanilla extracts are available. Natural vanilla flavouring contains real vanilla bean but no actual alcohol. Imitation vanilla extract is usually made by soaking alcohol into wood, which contains vanillin.