Double challenge: Double-Cola fights the soft drink wars with some basic weapons, including packaging innovations and a strong dose of service. (Cover Story)

The Double-Cola Co. is situated in a valley between the southern edges of the Appalachian Mountains and the Cumberland Plateau. * It's an appropriate home for the 67-year-old soft drink company, a small player in the valley between Coca-Cola and Pepsi-Cola. * For years, Double-Cola has battled the twin giants in its own backyard in Chattanooga, Tenn. In fact, the company's headquarters is at the foot of Lookout Mountain, home for much of the "old Coke Bottling money" - current and former executives who worked for the Chattanooga Coca-Cola Bottling Co. * Necessary and inevitable changes have transformed Double-Cola over the years. The company produces more than it did in the past and holds a 0.5 percent total share of the soft drink business. However, fewer people are needed today to produce its 38.5 million cases annually. This has left the 70,000-square-foot office and concentrate production facility fairly quiet. * In many ways, the building and its occupants haven't changed in years. Workers, some whom have been with Double-Cola for more than 30 years, still wear white slacks and white work shirts, although they don more familiar shoe brands like Nike. * While the look is of …