About this Article
Written by: Katrina Wu
Written on: December 10th, 2010
Tags: chemical engineering, food & drink
Thumbnail by: mluedtke/
About the Author
Katrina Wu was born in Los Angeles and raised between Los Angeles and Taipei. Currently finishing up her undergraduate studies at the Marshall School of Business in USC, the author looks forward to attending law school in the next fall to study environmental law.
Stay Connected

Volume XIII Issue I > Where Does My Decaf Come From?
Decaffeinated coffee is a popular beverage in cafes and homes throughout the world. There are several different methods used to decaffeinate coffee, including the direct method, indirect method, carbon dioxide method, and the Swiss Water Process. While the first three methods involve chemical treatment of the coffee beans, the last one—Swiss Water Process—does not involve any such treatment. Understanding the advantages and disadvantages of each method will help us to see why certain methods are more prevalent and advantageous in the decaffeination industry.
Figu​re 1: What's in your decaf?
In order to avoid experiencing insomnia or hyperactivity, many people choose to drink decaffeinated rather than caffeinated coffee. However, seldom do coffee drinkers ask about the steps taken to produce that cup of decaf coffee. A common misconception is that decaffeinated coffee comes from naturally grown coffee beans (Fig. 1) that are already decaffeinated in nature. While that may become a reality in the near future, currently decaffeinated coffee is derived from artificial processes that involve great engineering depths.
Certain types of coffee beans naturally contain less caffeine than others, but to achieve the decaffeination standard of less than 1% caffeine, coffee beans must be treated chemically to remove the caffeine. Coffee beans are always treated prior to roasting, or when they are still green beans, and there are generally five ways to decaffeinate coffee beans: Roselius, direct method, indirect method, carbon dioxide method, and Swiss Water Process. Presently, only four of the methods mentioned above—Roselius, direct, indirect, carbon dioxide—are used to decaffeinate beans [1]. The Swiss Water Process, inheriting a proprietary name, is an innovative process that differs from the rest of the methods and comes with its own set of advantages and disadvantages. Despite the widespread usage of these methods, what may threaten decaffeination companies but cause excitement among insomniac coffee lovers is the discovery of naturally decaf beans—Decaffito [2].


Roselius was the first decaffeination process developed. In 1903, Ludwig Roselius, a German coffee merchant, accidentally stumbled upon this method when his freight of coffee beans was soaked in sea water and lost much of its caffeine without losing much taste [3]. Thus, the Roselius process begins with a rinse-through of the unroasted coffee beans (green in color) in salt solution followed by repeated rinses (up to fifteen times) with benzene [3]. However, the use of benzene raised concerns for its health repercussions. The Roselius process is therefore no longer used.

Direct Method

The direct method, as its name implies, treats the beans directly with chemicals to remove the caffeine. Just like every other method of decaffeination, green coffee beans (unroasted beans) are soaked in water and then rinsed with either methylene chloride or ethyl acetate for ten or more hours to remove 99% of caffeine. Of the two types of chemicals, methylene chloride is more notorious for its carcinogenic properties, as confirmed by testing on lab rats, and even though the residual content of methylene chloride used is marginal enough to be acceptable by the FDA, in the long term it has the potential to cause harmful neurological effects, such as dizziness, loss of memory, changes in personality, and depression [4]. The other chemical in question, ethyl acetate, is often called the “natural process” because it is naturally produced in organisms such as ripened fruits in minuscule quantities [5]. However, despite ethyl acetate’s natural origins, the decaf process using ethyl acetate still involves larger quantities of the chemical than any naturally occurring process or organism.