Because the liquid is already full of coffee flavors, it doesn't extract any additional flavor from the coffee beans. It does, however, extract the caffeine. This cycle of soaking, then filtering out the caffeine, can be repeated indefinitely. The advantages of the water process over conventional methods is that no chemicals are used, so no residual chemicals are left in the beans. The environment, likewise, remains unaffected.
Most people seem to agree that the water process produces a slightly more flavorful cup of coffee.
Unfortunately water process coffee is also more expensive. In fact, Swiss Water Processed coffee is as much as four times as expensive as conventionally decaffeinated. For this reason the only roasters who use it are those whose customers are sensitive to health and environmental issues. In the CO2 decaffeination process, water soaked coffee beans are placed in a stainless steel container or extractor. The extractor is then sealed and liquid CO2 is injected.