“The method known as the Swiss Water Process, is based solely on water and carbon filtration. The coffee beans are first immersed in hot water to extract their caffeine and flavorful components. The initial beans are then discarded, and the resulting flavor-rich water (called “green coffee extract”) is passed through a carbon filter that is sized to capture only the large caffeine molecules. The decaffeinated green coffee extract is then used to wash and filter the next batch of beans. Caffeine is thereby filtered from the beans without recourse to chemical agents and without the beans losing many of their flavorful components. This is the primary method used to decaffeinate organic coffee beans.
Finally, the scientifically named supercritical carbon dioxide method uses carbon dioxide (CO2) under high temperatures and pressure to act like both a gas and a liquid. This supercritical CO2 reaches into the crevices of coffee beans like a gas but dissolves caffeine like a liquid. After the beans have been soaked in water (a process that expands cell structures and makes it easier to extract the caffeine molecules), they are exposed to supercritical CO2 for several hours. The caffeinated CO2 liquefies and evaporates, and the beans are then processed. Because this method leaves the carbohydrates and proteins intact, there is less change in taste as a result of decaffeination.”