The green beans enter a ‘pre-treatment’ vessel where they are cleaned and moistened with water before being brought into contact with pressurised liquid carbon dioxide. When the green coffee beans absorb the water, they expand and the pores are opened resulting in the caffeine molecules becoming mobile. After this water is added to essentially form sparkling water. The carbon dioxide circulates through the beans and acts like a magnet, drawing out the mobile caffeine molecules. The sparkling water then enters an evaporator which precipitates the caffeine rich carbon dioxide out of the water. The now caffeine free water is pumped back into the vessel for a new cycle. This cycle is repeated until the required residual caffeine level is reached. Once this has happened, the circulation of carbon dioxide is stopped and the green beans are discharged into a drier. The decaffeinated coffee is then gently dried until it reaches its original moisture content, after which it is ready for roasting.