Before we started testing the recipe for homemade root beer, we were curious about its principal aromatic ingredient, sassafras. Wasn't that substance illegal? Indeed, the FDA did ban safrole—a naturally occurring compound found in the oil of sassafrass root bark—for commercial use, but it is still relatively easy to find sassafras in health food stores, where it's sold as an anti-inflammatory. We wanted to see what the root bark looked like whole (it's usually available only in its crumbled form), so we asked Jeff Nordhaus of H&K Products in Columbus Grove, Ohio, a maker of sassafras tea concentrate, to send us some. When it arrived, we were surprised to see that it resembled oversize cinnamon sticks. Nordhaus gets his sassafras root bark from foragers who harvest it in the Appalachian, Ozark, and Smoky mountains. "They unearth the roots from about a third of the tree," he says. "All that good, sassafras flavor is in the rust-colored outer layer."