system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How come certain sodas (such as root beer or grape soda) are almost always caffeine free?
gpt
Caffeine is in colas because they were originally made with the kola nut, which has caffeine.  There's nothing in the ingredients of a rootbeer that would normally cause caffeine to be in the beverage unless you choose to add it.