Cramming Caffeine into the Stuff You Drink

Unless you've been asleep for most of your life, you've already figured out that coffee contains caffeine. But how do soft drinks and those ever-popular energy beverages wind up with a kick in the form of caffeine?

The simple answer is that caffeine gets sucked out of its naturally occurring form —  in beans, nuts, and plant leaves —  to be plopped into other products. The process is called decaffeination. Of course, decaffeinated drinks have their own fan base. Fortunately, the caffeine that's removed during decaffeination can be put to work elsewhere.

More than 60 different plants contain caffeine. Coffee beans come from the arabica plant. The Thea sinensis plant gives up its leaves for teas, and the Theobroma cacao tree graces the world with cocoa beans, the basic ingredient in chocolate.

Separating the white, powdery, bitter-tasting stimulant from its natural source can be done several ways. If you're in the mood to impress your chemistry teacher, here's a rundown of methods for removing caffeine from the plants that pack the original wallop:

  • Methylene chloride processing — Caffeine molecules bond to methylene chloride molecules. So, scientists set up a sort of swimming pool where molecules can get up close and personal — just the right recipe for extracting that friendly alkaloid. (Other alkaloids include nicotine, cocaine, and morphine.)

  • Ethyl acetate processing — The operation is pretty much the same as with methylene chloride, with one key variation. Ethyl acetate is a chemical that shows up naturally in lots of fruits, so when it's used as a solvent for molecule bonding with caffeine, the process yield products that are "naturally decaffeinated."

  • Carbon dioxide processing — In a pressure-cooked state, carbon dioxide acts as both a gas and a liquid. The chemical's smaller molecules whistle for caffeine molecules that are about the same size. (Who said opposites attract?) Flavor molecules are bigger, so they're retained in the coffee, tea, or cola that's being decaffeinated.

  • Water processing — This method requires no chemicals for extraction. Instead, hot water helps leach caffeine out of its source, and a carbon filter collects the escaping compound.

These processes separate out some, but not all, of the caffeine from its natural "host." U.S. federal regulations call for caffeine levels in a product to be below 2.5% for the product to be considered decaffeinated.

The removal process makes caffeine available for products like cold medicines, stay-awake pills, soft drinks, and sodas packed with an eye-opening punch. Interestingly, less than 5% of caffeine in cola beverages comes from a naturally occurring source, the kola nut. Colas typically get their buzz power from the addition of caffeine pulled out of plant forms during the decaffeination process.