The Flavor of the Malt
All spirits have a given percentage of the primary ingredients, water and ethanol. The differences between cheap and expensive liquors, therefore, arise in the unique flavors and aromas particular to different types and brands. These unique flavors are the result of trace amounts of "impurities" in the liquor. Sometimes producers intentionally add characteristic "impurities" to "tag" their product. In other cases, these adulterations have been added coincidently with the producer's water supply used for the whiskey, the soil type in which the grain or cereal was grown, the choice of cereal or grain itself, how and in what the liquor is aged, etc. For example, Jack Daniel's whiskey (produced in Lynchburg, Tennessee) is made from the iron-free water from a naturally spring-fed limestone cave. Jack Daniel's also "mellows" their whiskey by slowly filtering their newly-made whiskey through giant ten-foot columns of hard-packed sugar maple wood charcoal.
They then age their whiskey in "flame-charred" American White Oak barrels for many months. Each element in the production process, the limestone cave spring water, the charcoal "mellowing", and the oak barrel aging contributes unique "impurities" to the final product which we perceive as a characteristic flavor (www. JackDaniels.com).
For this project, we have investigated and compared the organic compounds that contribute to flavor, in Jack Daniels Whiskey, Smirnoff Vodka, Captain Morgan's Rum, and Glenfiddich Scottish Whiskey. Capillary gas chromatography is a useful technique for measuring such differences in the components of these liquors. By comparing retention times of organic components coming off in the whiskey, vodka, and rum samples with the retention times of known standards, one can determine the exact components in each spirit. Determination of these components then illustrates the complexity of each spirit as well as differences between them which humans perceive as flavor.