Today’s sophisticated spectrometers, gas chromatographs, and headspace-vapor analyzers provide a detailed map of a food’s flavor components, detecting chemical aromas present in amounts as low as one part per billion. The human nose, however, is even more sensitive. A nose can detect aromas present in quantities of a few parts per trillion — an amount equivalent to about 0.000000000003 percent. Complex aromas, such as those of coffee and roasted meat, are composed of volatile gases from nearly a thousand different chemicals. The smell of a strawberry arises from the interaction of about 350 chemicals that are present in minute amounts. The quality that people seek most of all in a food — flavor — is usually present in a quantity too infinitesimal to be measured in traditional culinary terms such as ounces or teaspoons. The chemical that provides the dominant flavor of bell pepper can be tasted in amounts as low as 0.02 parts per billion; one drop is sufficient to add flavor to five average-size swimming pools. The flavor additive usually comes next to last in a processed food’s list of ingredients and often costs less than its packaging. Soft drinks contain a larger proportion of flavor additives than most products. The flavor in a twelve-ounce can of Coke costs about half a cent.