The base tea for our Evening Earl Grey has been produced using a completely natural CO2 decaffeination method; essentially the tea is “pressure cooked” with this naturally occurring gas. At high pressures and high temperatures, carbon dioxide reaches a supercritical state. The CO2 becomes a solvent and its small, nonpolar molecules attract the small caffeine molecules. Since flavour molecules are larger, they remain intact, and also retain a high percentage of polyphenols. After passing through the tea leaves, the caffeine-laden CO2 is filtered to remove the caffeine, which is then sold to be used in canned drinks with extra caffeine!
The decaffeination process leaves a minute amount of caffeine in the leaf. By law, tea labelled as “decaffeinated” must have less than 2.5 percent of its original caffeine level, which usually equates to less than 2 mg per cup.