How Do They Decaffeinate Coffee?

How Caffeine Is Removed From Coffee

Caffeine occurs naturally in more than 60 different plants. Coffee is one of them. Caffeine stimulates our minds and affects our bodies. The thing is that some of us, for one reason or another, want to restrict the amount of caffeine we get in our coffee. The demand for decaffeinated coffee is so great that approximately fifteen percent of the coffee that is sold is decaf. This has created a need for a safe, cost-effective method of removing caffeine from the coffee beans.

In most processes, the beans are washed with a solvent which removes the caffeine.

The Roselius Process
In 1903, the first successful commercial decaffeination process was invented by Ludwig Roselius and Karl Wimmer. This process used steam to soften the beans, then benzene was used as a solvent to remove the caffeine from the coffee. This process is no longer used due to health risks associated to benzene.

Direct Method
When this method is used the beans are first steamed then they are rinsed with dichloromethane or ethyl acetate to remove the caffeine. The beans are then steamed again to remove the solvent from the beans. This process takes over 20 hours to complete.

Indirect Method
With this method, the beans are soaked in hot water for several hours, then they are rinsed with dichloromethane or ethyl acetate to remove the caffeine. This process causes less loss of flavor due to the fact that the water part of the process creates what is essentially a strong pot of coffee. There is less loss of flavor for this reason. Beans processed with this method are often labeled "water processed," which seems inaccurate since chemicals are used in the process.

CO₂ Process
Beans are steamed, then soaked in a bath of carbon dioxide at a pressure of 73 to 300 atmospheres (1,073 - 4,409 psi) and 200° F. The CO₂ and caffeine are removed by simply lowering the pressure and allowing the carbon dioxide to evaporate, or by rinsing with water or by using charcoal filters.

Triglyceride Process
In this method, beans are soaked in a hot water/coffee solution, then the beans are moved to another vessel where they are immersed in oils that came from spent coffee grounds. These oils are at a high temperature, and the triglycerides in the oils remove the caffeine from the beans.

Swiss Water Process
This process uses coffee that has no caffeine in it to extract the caffeine from the coffee beans. The solution goes through a carbon filter to remove the caffeine. See the video clip below for details - the video is a bit corny, but it is very informative.

An Additional Note
Because Ethyl Acetate occurs naturally in some fruits, coffee that has been decaffeinated with this method is often referred to as "naturally decaffeinated." This is interesting, as the Ethyl Acetate that is used to process most coffee is made synthetically. As a former chemical plant operator of 10 years, this bothers me - sorry, it is just my view on it.