Caffeine is a polar molecule. This property of caffeine makes it possible to remove caffeine molecules easily from coffee beans, cocoa and tea leaves, making them 97 percent caffeine-free. Using the principle of "like dissolves like," polar solvents are used to extract caffeine from these food products.
Depending on the process, ethyl acetate or methylene chloride, which are polar solvents, may be used to decaffeinate coffee beans. The steamed coffee beans are rinsed in the polar solvents, and the caffeine molecules bind to the molecules of the solvent. Then, the coffee beans are steamed again to remove remaining solvents, thus producing decaffeinated coffee. The extracted caffeine is further processed and used in the food and pharmaceutical industries.