Root beer is a carbonated, sweetened beverage, originally made using the root of the sassafras tree, or its bark, as the primary flavor. Root beer, popularized in North America, comes in two forms: alcoholic and soft drink. The historical root beer was analogous to small beer in that the process provided a drink with a very low alcohol content. Although roots are used as the source of many soft drinks throughout the world, often different names are used.
There are many root beer brands throughout the United States and it is produced in every U.S. state. It is a flavor almost exclusive to North America, yet there are a few brands from other nations around the world, such as South Korea, the Philippines and Thailand where the flavor often varies slightly from the typical North American drink. There is no standardized recipe. The primary ingredient, artificial sassafras flavoring, is complemented with other flavors. The flavor in sassafras, safrole, is banned in the United States and European Union as a likely carcinogen. Common flavorings are vanilla, wintergreen, cherry tree bark, licorice root, sarsaparilla root, nutmeg, acacia, anise, molasses, cinnamon, and honey.
Homemade root beer is usually made with extract obtained from a factory, though it can also be made from actual herbs and roots. Both alcoholic and non-alcoholic root beers have a thick and foamy head when poured, often enhanced by the addition of yucca extract.
The custom of brewing root beer goes back to the 18th century when Samuel Adams commissioned a brewed beverage that his children could drink. Farm owners used to brew their own (then) light-alcoholic beverage for family get-togethers and secret services in the woods. During the 19th century, some pharmacists tried to sell their version of root beer as a miracle drug.
In 1876, pharmacist Charles Hires first introduced a commercial version at the Philadelphia Centennial Exhibition. Hires was a teetotaler who wanted to call the beverage "root tea". However, his desire to market the product to Pennsylvania coal miners caused him to call his product "root beer" instead. By 1893, root beer was sold as a bottled soft drink to the public. Especially during Prohibition, non-alcoholic versions proved to be commercially successful.
In 1960, a key ingredient (the sassafras root) came to be known as a carcinogen and its use was banned by the U.S. Food and Drug Administration. Following this ban, companies began experimentation with artificial flavors and preparation techniques to remove the unhealthy effects of root beer while preserving its flavor.
- Sassafras albidum – Sassafras (roots) – safrole. The oil from these roots is believed to be carcinogenic so artificial versions are generally used instead. However, natural extracts with the safrole distilled and removed are available.
- Smilax regelii – Sarsaparilla.
- Smilax glyciphylla – Sweet Sarsaparilla.
- Piper auritum – Root Beer Plant or Hoja Santa.
- Glycyrrhiza glabra – Liquorice (root).
- Aralia nudicaulis – Wild Sarsaparilla or "Rabbit Root".
- Gaultheria procumbens – Wintergreen (leaves and berries).
- Betula lenta – Sweet Birch (sap/syrup/resin).
- Betula nigra – Black Birch (sap/syrup/resin).
- Prunus serotina – Black Cherry.
- Picea rubens – Red Spruce.
- Picea mariana – Black Spruce.
- Picea sitchensis – Sitka Spruce.
- Arctium lappa – Burdock (root).
- Taraxacum officinale – Dandelion (root).
- Pimenta dioica – Allspice.
- Theobroma cacao – Chocolate.
- Trigonella foenum-graecum – Fenugreek.
- Myroxylon balsamum – Tolu balsam.
- Abies balsamea – Balsam Fir.
- Myristica fragrans – Nutmeg.
- Cinnamomum verum – Cinnamon (bark).
- Cinnamomum aromaticum – Cassia (bark).
- Syzygium aromaticum – Clove.
- Foeniculum vulgare – Fennel (seed).
- Zingiber officinale – Ginger (stem/rhizome).
- Illicium verum – Star Anise.
- Pimpinella anisum – Anise.
- Humulus lupulus – Hops.
- Mentha species – Mint.
- Root Beer World (Brand Database)
- Anthony's Root Beer Barrel
- Root beers that contain caffeine
- MAKING ROOT BEER AT HOME by David B. Fankhauser
- The History of Root Beer
- Funderburg, Anne Cooper (2002). Sundae Best: A History of Soda Fountains.
- Title 21 Code of Federal Regulations, Sec. 189.180: Department of Health and Human Services, 2013 
- Dietz, B; Bolton, Jl (Apr 2007). "Botanical Dietary Supplements Gone Bad".