How Decaffeinated Coffee is Made

Decaffeinated coffee is made by removing the caffeine from coffee beans before they are roasted. There are several methods to decaffeinate coffee, and here are some of the most common ones:

1. Swiss Water Process: This is a chemical-free method, and it uses water from the pristine environment of the coast mountains of British Columbia, Canada. The process involves soaking the green (unroasted) coffee beans in hot water, which dissolves the caffeine. This mixture is then passed through a charcoal filter that traps the caffeine molecules but allows the water and other molecules that contribute to coffee flavor to pass through. The coffee beans are then discarded, and the caffeine-free water—rich in flavor compounds—is used to soak a new batch of beans. The flavor compounds stay in the beans while the caffeine gets extracted again. The process is repeated until 99.9% of caffeine is removed.
2. Direct Solvent Process: In this method, the green coffee beans are first steamed and then rinsed with a solvent (typically methylene chloride or ethyl acetate), which bonds with the caffeine molecules. This solvent-caffeine combination is then rinsed away with water. The beans are steamed again to remove any remaining solvent. This method can remove up to 96-97% of caffeine.
3. Indirect Solvent Process (or Solvent Water Process): The coffee beans are first soaked in hot water for several hours, which extracts the caffeine as well as other flavor oils and compounds. The water is then drained off and the beans are washed with a solvent for about 10 hours. The solvent bonds with the caffeine and is subsequently drained off. The beans are then re-soaked in the water to reabsorb the flavor oils and compounds. This process removes about 94-96% of caffeine.
4. Carbon Dioxide (CO2) Process: This method takes advantage of supercritical carbon dioxide, which is a state of carbon dioxide where it acts both as a gas and a liquid. The green coffee beans are soaked in water and then placed in a stainless steel extraction vessel. The vessel is then sealed and liquid CO2 is forced into the coffee at pressures of 1,000 pounds per square inch to extract the caffeine. The CO2 acts as the solvent to dissolve and draw the caffeine from the coffee beans, leaving the larger-molecule flavor components behind. The caffeine-laden CO2 is then transferred to another container (the absorption chamber) where the pressure is released, and the CO2 returns to its gaseous state, leaving the caffeine behind. The caffeine-free CO2 is pumped back into the vessel with the beans to remove any remaining caffeine. This process can remove 97% of caffeine.