In the direct solvent extraction process, decaffeination is accomplished by direct application of methylene chloride, ethyl acetate or carbon dioxide to the coffee beans. The beans are then steamed to remove the residual solvent, then dried and roasted. Methylene chloride received a great deal of attention when it was found to be an animal carcinogen when given by inhalation. An average 5 ounce cup of tea can contain 20-ll0 mg, making it the next highest source of caffeine in beverages. How much caffeine is in your cup of tea will depend upon the type of tea used, the tea leaf cut, and how long it was brewed.
Tea also contains theophylline, another member of the xanthine family of stimulants.
Therapeutically, theophylline is sometimes used in the treatment of congestive heart failure, hyperactivity in children, and as a bronchial dilator in the treatment of asthma. An average 5 ounce cup of tea contains about 1 mg of theophylline and 50 mg of caffeine. The level of caffeine found in a particular brand is consistent from can to can because of strict manufacturing controls. Only those soft drinks containing caffeine will show it as an ingredient on the product label. To compare brand names, see the chart below.