Decaffeination can be accomplished using various processes. Most common is immersing the green coffee in a chemical bath. Another less common method is a bath in carbon dioxide gas. The process used in all the decaf coffees we sell is the water process, immersing beans in water which pulls out the caffeine. All our beans are either 'Swiss Water Processed' SWP or 'Water Processed' WP. Both use virtually the same method, SWP is by a particular company. WP is a generic version of the same method.