Look at the ingredients of Coca-Cola, they are

Carbonated water, high fructose corn syrup and/or sucrose, caramel color, phosphoric acid, natural flavors, and caffeine

The secret to the taste of Coca-Cola is in the "natural flavors", also known by the infamous code name of 7x.

In 1993, author Mark Pendergrast published his book, For God, Country and Coca-Cola, in which he (with Coca-Cola Company approval) divulges the ingredients list found in the original laboratory notebook of Dr. John Pemberton, the creator of the original Coke recipe:

Company officials confirmed that this was indeed the original recipe for 7x. Though the general recipe for coke has been altered several times since its first formulation* by Dr. Pemberton in Atlanta in 1886, the components that go into 7x have, according to company statements, remained unchanged. However, it is been rumored that Asa Candler, after purchasing the fledglingCoca-Cola company in 1889, added Oil of Lime to the 7x formula in order to foil competitors -- and modern-day chemical analysis of Coca-Cola indicates that this is probably the case.

Despite the fact that the general recipe is now in the open, Coca-Cola insists that the exact method and order by which the 7x components are blended is critical to the unique taste of Coca-Cola -- and knowledge of this process is still a closely guarded secret. Incidentally, though the secrecy of Coca-Cola is maintained for competitive reasons, it is speculated that Dr. Pemberton kept his original recipe secret for a very different reason: according to Atlanta's prohibition laws at the time, it was illeagal to own the ethanol needed to dissolve the six oils.

*That is, they removed all extracts of the Coca plant and the Kola nut =P, switched from sugar to corn syrup and from citric acid to phosphoric acid. In addition, some consipiracy theorists and die-hard cola fans believe that different formulas for Coke are distributed nationwide in order to cater to differing regional tastes: the South likes a sweeter cola while the Northeast likes it with more carbonation. Perhaps at the next noder gathering, we can bring our regional cokes and do a little taste test = )

This writeup made possible by SodaMuseum.com