On one hand, coffee is well-known to discolor teeth.

On the other hand, Kool-Aid can "stick" to teeth for quite awhile after drinking it. (Teeth are purple for awhile after drinking grape, or red after drinking cherry, etc.) Let’s assume it’s sugar-free Kool-Aid to avoid confusing the issue with concerns about tooth decay.

So, which beverage discolors teeth more in the long-run?