The first time I ever tried root beer, I exclaimed, "This tastes like sassafras tea!" And my classmates looked at me like I'd grown two heads. My family did not buy soda pop, but Dad taught me how to identify a sassafras tree and dig up roots to make tea. The sassafras taste comes from safrole, which is banned because in high doses it can cause liver cancer in lab rats. So now, root beer and sassafras tea are made with artificial flavorings.
Zach Armstrong of LabCoatz is an avid root beer fan, so he made his own. The process ranges from old-timey foraging for sassafras root to the lab chemistry of distilling and isolating the safrole. Then we get a recipe for root beer. Sassafras tea from my childhood was much simpler: boil the sassafras root in water, and add sugar if you want. The root beer part of this video ends at 10:22. (via Digg)