Guide to Decaffeinated Coffee Methods

Drinking decaf doesn’t mean selling out on flavor, aroma or quality. . .  It should taste the same as caffeinated coffee if the caffeine is removed properly. —ROSEMARY FURFARO,

Different terms with one meaning: Kaffee Hag in Germany, Sans caffeine (“Sanka”) in France, and Dekafa in the United States.

The reason behind decaffeinated coffee
For those people who react badly to caffeine or who do not wish to become addicted and suffer withdrawal headaches or who want to drink coffee just before bedtime, decaffeinated coffee provides an alternative.

The majority of caffeine-free coffee sold in specialty stores is initially shipped to decaffeinating plants in Switzerland and Germany. It is in these countries that the majority of all decaffeinated coffees are produced. Once the processing is complete, they are then shipped back to North America. Decaffeinated coffee originated in Germany over one hundred years ago. It may be comforting to know that the processing standards are scrupulous and the quality controls of the decaffeination facilities are superior.


The U.S. Food and Drug Administration requires that coffee must have 97 percent of the caffeine removed from the untreated green beans to qualify as “decaffeinated.” When you are purchasing decaffeinated coffee, check to see if the decaf is an arabica or robusta blend. Depending on the type of bean and/or blend, the amount of caffeine that remains in the finished product can also vary. For example, the amount of caffeine in a decaffeinated 100 percent robusta coffee will be naturally higher than a 100 percent Arabica coffee since robusta beans have almost twice as much caffeine in their natural state as do arabica coffee beans.

Traditionally, inferior robusta beans are chosen for decaffeination because they yield a higher caffeine by-product, which is sold for medicinal and soft drink purposes. However, more and more arabica coffee beans are being decaffeinated, for their superior finished coffee flavor, aroma, and body, and certainly for the greatest benefit, a lower-caffeine coffee product!

Decaffeination Processing Methods

The process of decaffeinating coffee began at the turn of the last century, in Germany. Although there have been many patents since today there are only three primary decaffeination methods used by the coffee industry. Each process begins the same way: the green (unroasted) coffee beans are moistened with steam and water to soften them, open their pores, and loosen their caffeine bonds. After this initial step, the following various methods are used. These methods are conventionally named according to the process.

¨Water only¨ Method: the Swiss Water Process

Swiss water decaffeination almost always uses high-quality arabica beans. Thus, the final higher-quality product is reflected in a more expensive price tag. Essentially, you get what you pay for. This process does not use chemicals. First, the caffeine, as well as the flavor extracts, is stripped from the beans by the initial water and steam soak. This first batch of beans is discarded. The water, which now holds the coffee flavor extracts and caffeine, is filtered through carbon to remove the caffeine.

Now only the “coffee-flavor-charged” extract (caffeine-free) solution remains. It is this extract that is used to subsequently absorb the caffeine from a new batch of beans. Due to the scientific principles of solubility, the caffeine in the new batch of coffee beans moves from an area of higher concentration (the bean itself) to an area of lower concentration (the extract). By this process, 94 to 96 percent of the caffeine is removed. Since this process uses no chemicals aside from the carbon filter (the same substance as is used to purify water), it is referred to as an organic, or natural, method.

The Water Decaffeination Method

In a water decaffeination process that is not specifically “Swiss,” sometimes chemicals, rather than charcoal filters, are used to extract the caffeine from the “coffee-flavor-charged” extract. It is important to note that this chemical solvent does not come into contact with the actual beans. The beans come into contact with water only, and the rich aroma and flavor characteristics of the coffee are minimally altered.

The Solvent Method

Certain solvents, such as methylene chloride and common ethyl acetate, are the most widely used chemical compounds to decaffeinate coffee. Although synthetic methylene chloride has been under fire as regards being hazardous to the environment, its use is allowed, providing the residues to fall below certain limits.
Ethyl acetate may be sourced from natural ingredients, and it can be produced synthetically as well. This method is generally advertised as a “naturally” decaffeinated process. Unfortunately, there is no way of knowing whether the solvent source is natural or synthetic.

The Solvent-Touches-the-Bean Method

After the initial moistened phase, the solvent circulates through the beans, removing the caffeine. The beans are then rinsed with water and steamed once more, thereby easily evaporating any residual solvent, and finally dried. The beans are then sold to be roasted, and the extracted caffeine is sold for medicinal uses and soft drinks. This chemical caffeine method removes 96 to 98 percent of the caffeine.

The Solvent-Never-Touches-the-Bean Method

After the initial moistened phase, when the hot water bath has soaked the caffeine and the coffee extracts from the beans, the “flavor-charged” water is separated from the stripped beans and combined with a solvent, which unites with the caffeine. The solvent carrying the caffeine is then removed, and the flavor-charged caffeine-free water is reunited with the stripped coffee beans, to reabsorb the coffee flavors and oils. It is important to note that when this method is used, the solvent never touches the bean itself. Again, any residual solvent is evaporated in the final steaming phase, or during the roasting process of the coffee bean.

The “Supercritical” Carbon Dioxide Method

Once again, after the initial moistening phase, the coffee beans that are being decaffeinated are put into an extractor. Pressurized “supercritical” carbon dioxide is used at 250 to 300 times its normal atmospheric pressure. At this pressure, the carbon dioxide turns somewhat into a fluid, having a form between a liquid and a gas. When this “supercritical” solvent passes through the coffee beans, the caffeine migrates to it.

The now-caffeine-rich solvent passes through a filter, to absorb the caffeine for reuse. When its work is done, and the pressure released, the solvent turns back into a gas and dissipates. Carbon dioxide is inexpensive to obtain and is nontoxic. This supercritical carbon dioxide method removes 96 to 98 percent of the caffeine without removing other coffee flavor characteristics.

Interestingly, whatever method they use, there are very few decaffeination processing plants in the world, because they are very, very expensive to operate. This is also one reason why decaffeinated coffee is more expensive to purchase than regular coffee.

this is the end: Decaffeinated Coffee Methods

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