This process uses liquid carbon dioxide to remove the caffeine from the coffee beans. The beans are treated in a container with carbon dioxide at high pressure and low temperature, which extracts the caffeine. This process is gentler than the solvent process and is considered safer, but it has the disadvantage of being more expensive.
And this is how Co2 decaffeination works in detail:
- The green coffee beans are placed in a pressure vessel and flooded with liquid carbon dioxide. This causes the caffeine to dissolve from the beans and pass into the carbon dioxide.
- The carbon dioxide is then pumped out of the container and into a second container where the carbon dioxide is under low pressure and high temperature. These conditions separate the caffeine from the carbon dioxide and it can later be disposed of or reused.
- The decaffeinated coffee beans are removed from the pressure vessel and thoroughly cleaned to remove any residue.
- The coffee beans are then roasted and further processed like ordinary coffee beans.
Carbon dioxide decaffeination is mainly carried out in coffee-producing countries such as Colombia, Mexico, Brazil and Costa Rica, but also in Europe and the USA. However, it is also used by some specialised coffee producers around the world.
It is possible to decaffeinate beans regardless of their variety, Arabica or Robusta. However, most producers tend to choose Arabica beans as they are usually of higher quality and have a better taste.