[dimaggiosghost]

Did you mean that it's not common in root beer? Wiki says that root beer has little to no caffeine.

Root beer is so sweet that I would think it could mask the bitterness. I wonder if the plants that originally were brewed into it just didn't have any caffeine.

Do the ingredients to coke naturally have caffeine, or was that a substitute for the original alkaloid? I.e., is decaf coke because the removed the caffeine, or is caffeinated coke that way because it was added?

[mathw]

Coca-Cola lists caffeine as an ingredient in the UK.

I don't know why caffeine was originally added - maybe for flavour, maybe for the stimulant effects, possibly because of having to not have cocaine in it anymore...

[detaro]

The "original" Coca-Cola had caffeine as well - it's in the cola nut, which is where the "cola" part of the name comes from.

[adrianmonk]

Root beer doesn't naturally have caffeine, but sometimes it's added for flavor.