The KVW Decaffeination method is a solvent-based process for decaffeinating unroasted coffee beans, using the solvent methylene chloride to remove caffeine. This process is noted for maintaining more of the original flavor of the coffee beans than many other methods.
In this process, the coffee beans are soaked in hot water to extract much of the caffeine from the beans. The beans are removed from the water and then the methylene chloride solvent is added to bond with the caffeine. After the methylene chloride/caffeine compound is skimmed from the surface of the mixture, the beans are returned to reabsorb the liquid. The KVW method of decaffeination removes between 96 to 97% of caffeine from a batch of coffee.
Is it safe?
While methylene chloride is a toxic chemical solvent, its use in the KVW decaffeination process is generally not considered a health risk. While it is possible that there will remain an amount of methylene chloride in the decaffeinated beans, it is considered unlikely that it will survive the roasting and brewing process. This is supported because methylene chloride evaporates at 40°C while roasting of coffee beans is carried out in ovens which obtain temperatures in excess of 200°C.