We're All Swiss - About Decaf.
There are only a couple of ways really to take a green coffee bean and 'decaffeinate' it. One is soaking the beans in chemicals and the other is the Swiss Water Process, a method of decaffeinating coffee beans developed by the Swiss Water Decaffeinated Coffee Company.
To decaffeinate the coffee bean by the Swiss Water method, a batch of green (unroasted) beans is soaked in hot water, releasing caffeine. When all the caffeine and coffee solids are released into the water, the beans are discarded. The water then passes through a carbon filter that traps caffeine but lets the coffee solids pass through. The resulting solution, called "green coffee extract (GCE)" by the company, is now available for decaffeinating coffee. New green coffee beans are introduced to the GCE. Since the GCE is coffee solids without caffeine, only the caffeine diffuses from the new beans. The GCE passes through proprietary carbon, which captures the caffeine. The process repeats, filtering out all the caffeine until the beans are 99.9% caffeine-free. These beans are removed and dried, and thus retain most if not all of their flavor.