Swiss water processing is a process that is a one-hundred percent chemical-free coffee decaffeination process that is used to produce most decaffeinated coffees today. In this process, water is used to remove the caffeine from coffee. Most of the previously used processes used such chemical solvents as Methylene Chloride. Theses processes are known as the Roselius process, the CO2/O2 process, and the Triglyceride process.
The Swiss water process was invented when scientists took some grown coffee beans that were full of flavor and immersed them into water. With the beans in the water, both the coffee flavor solids and caffeine were extracted from the beans. The beans were then discarded and the caffeine was removed using a carbon filter, which in essence only left the water and coffee flavor solids.
How this chemical-free decaffeination works is due to the coffee beans being soaked in water that partially saturated with coffee flavor solids. After the beans have soaked in the water, they immersion in this flavor-charged water results in some interesting chemistry. The water is caffeine-free but heavily laden with coffee flavor compounds, so when the beans are in the water, only the caffeine in the beans separates into the water. After the caffeine is removed from the beans and into the water, the water passes through a carbon filter that then traps the caffeine. The flavor-charged caffeine-free water then flows back to the beans to remove more caffeine. This process continues until the beans are 99.9% caffeine-free and takes approximately eight hours.
After the decaffeination process is complete, the trapped caffeine is then removed from the carbon filter. The flavor compound-saturated water is then recycled to start the process over again for the next batch of beans.
Decaffeinated Coffee from Chemical Solvents
Approximately 80% of all decaffeinated coffee is decaffeinated with a chemical decaffeination method that uses chemicals like Methylene Chloride or Ethyl Acetate. How the chemical decaffeination processes work is the beans are first soaked into a caffeine absorbing solvent. After the beans have been soaked, the solvent, which now contains the caffeine, is separated from the beans. The caffeine is then removed from the solvent. Lastly, the first three steps are repeated over and over until sufficient caffeine is removed from the beans.
Caffeine is a natural substance that is present in the leaves, seeds, and fruits of more than 60 different species of plants worldwide. The caffeine content of decaffeinated coffee can alter based on blend composition, brewing extraction rates, grind, roast color, and water temperature. Other elements that result in a higher caffeine content is higher extraction rates, warmer water, a finer grind, and a lighter roast.