How is the decaffeinated process in decaf coffee done?

Common knowledge - Written: Taki Tiến Nguyễn


14:53 13/09/2022

CFRR – Decaf coffee (decaffeinated coffee) is known as a caffeine-free coffee, is that true, and what would it taste

Most people drink coffee because the caffeine inside helps to wake up and increase the ability to focus on work. Some people who are not passionate about coffee will choose tea or other beverages to get the best result, sober spirit for all day. But the ability to tolerate caffeine in each person is different, so it can easily lead to difficulty sleeping or insomnia at night. Decaffeinated coffee now becomes significantly more effective.

Accepting that caffeine is a naturally occurring substance in coffee, eliminating caffeine for some people considers it an act that goes against the order of nature though they don’t like it. However, about 10% of people choose to enjoy the taste of coffee without the stimulant effects of caffeine.

General characteristics when decaffeinated 

According to the USDA (US Department of Agriculture), decaffeinated does not mean caffeine-free 100% it reality can only reduce about 97% of caffeine. That means a 50gram cup of espresso has a caffeine content of about 120mg would be about 36mg of caffeine after decaffeination.

Decaffeinating in green coffee beans without affecting the flavor of the brewed coffee has led researchers to devise different decaffeination techniques. They include several solvents, organic solvents, water decaffeinated techniques, or supercritical carbon dioxide for decaffeination.

Regardless of the technique applied, the decaffeinated coffee beans must be green coffee beans that have not undergone the roasting process. Caffeine is a water-soluble substance, so the decaffeinated process will take p in water that can dissolve other soluble substances in coffee. It needs more decaffeinated to speed up the process without compromising the dissolution of other substances caused by water affecting the taste of decaf coffee.

The Roselius process 

Ludwig Roselius. Photo: Darrin’s Coffee

The first decaffeinated process was invented by Ludwig Roselius in 1903 and patented in 1906. Legend has it that he thought caffeine was poison to his father when he drank too much coffee, which prompted him to find ways to eliminate it by searching for substances that could reduce caffeine.

In the Roselius process, the green coffee beans were soaked with a saline solution, after which he used benzene organic chemical compounds as solvents to extract the caffeine. However, benzene had identified possible carcinogens for the body, so this procedure had discontinued.

The methods used to decaffeinate 

Current decaffeinated techniques had based on the Roselius process but using other organic solvents as an alternative to benzene or non-solvent-based reduction processes is presented as follows.

Process for decaffeination using ethyl acetate organic solvent 

This method is also known as the “Natural decaffeinated method” or the “Ethyl acetate method.”

Process for decaffeination using ethyl acetate organic solvent. Photo: cafeimports

In this technique, the process is carried out in the order shown below, with the first step used the beans are green coffee beans (1) These beans will be steamed hot under low pressure for 30 minutes ( 2) and opened up the vents of the coffee allowing caffeine extracted (3), the green coffee beans then placed in a solution of water and ethyl acetate (EA) (4), which reacts with the chlorogenic acid salts in the coffee, allowing the caffeine to be extracted (5). After about 8 hours, the coffee beans are continuously to wash away the caffeine with methyl acetate, caffeine-containing solvent has discharged to the outside through the exit valve (6), the obtained green coffee beans (7) must undergo a process again under low pressure to remove the remaining ethyl acetate (8). The decaffeinated coffee is then dried, physically polished to ensure cleanliness, and packaged (9).

Ethyl acetate (CH3CO2C2H5) has been identified as a naturally occurring substance because it is present in ripe fruits such as apples and blackberries, making ethyl acetate a natural decaffeinated method. Ethyl acetate in nature is difficult to obtain from fruit and because of its cost, the ethyl acetate used for decaffeination will be a synthetic substance from ethyl alcohol and acetic acid.

Swiss water decaffeinated process (SWP) 

The chemical-free water decaffeinated process was applied foremost in Switzerland in 1933, and in 1988 the Swiss water method was introduced to the market. And the Swiss water decaffeinated method is the only facility in the world certified by OCIA (Organic Crop Improvement Association) and Aurora Certified Organic (Aurora Certified Organic).

The green coffee beans are first soaked in hot water to dissolve the caffeine, then water is drawn out and passed through a filter with activated carbon. The filter’s porosity has a suitable size to trap the caffeine and allow flavor and oil molecules to pass through it. At the end of this phase, decaffeinated and unflavored coffee beans are in one tank, and flavored water without caffeine (green coffee extract) is in another.

Swiss water decaffeinated process (SWP). Photo: propellercoffee

The coffee beans that are noncaffeine and unflavored has discarded. Fully flavored water must use to remove the caffeine in a new batch of beans. Since this water has already saturated with flavor ingredients, in the decaffeinated coffee beans, flavors will not dissolve only the caffeine will be dissolved in the water. The result is decaffeinated coffee that retains the flavor in the beans. This method is also known as “Swiss water” decaf.

Carbon dioxide decaffeinated process (CO2) 

The CO2 decaffeinated method is the latest method developed by Kurt Zosel that uses liquid CO2 instead of a chemical solvent. Coffee beans have soaked with water in an extractor made from stainless steel. Then a liquefied amount of CO2 under a pressure of more than 450kg and a temperature of 93oC is pushed inside the extraction vessel to extract the caffeine, releasing the alkaloids without affecting the other flavor compounds. Caffeine-containing CO2 has poured into another container called an absorption chamber which the pressure is down to make CO2 from the liquid form return to a gaseous state and then reduced for later use.

Carbon dioxide decaffeinated process (CO2).
Photo: Biruk and coworkers (2019)

The carbon dioxide (CO2) decaffeinated process used by selective action for caffeine is highly effective. However, the high cost due to industrial equipment under high pressure and a system with a large amount of CO2 recovered is quite complex, so it has not been applied in the market.

Is decaf coffee good to drink? 

Our process is inevitable in the loss of flavor compounds that contribute to the organoleptic characteristics of roasted coffee beans. “Decaf coffee” is considered a coffee difficult for roasters because green coffee beans go through the decaffeinated process.

And the color of the beans almost turns brown, not green, making it difficult for roasters to control and to have a heterogeneous and excessive response to the heat applied to them during roasting. Decaf coffee beans tend to be roasted with a darker color and have a quicker roasting time than regular coffee beans. And there is another market factor when the price of decaf coffee is almost the same as that of regular coffee as it costs more, and producers will choose inferior quality coffee beans to decaf coffee. So, for a long time, decaf coffee has been labeled by users as “not good” compared to regular coffee.


Although most drinkers look forward to the flavor in coffee and the stimulating effect of caffeine, everyone’s tolerance to caffeine will vary even though for those who are very sensitive to caffeine, decaf coffee is an optimal choice for users.


Biruk Ayalew, Adugna Debela. 2019. Shade and Nitrogen Levels Affected Physiological and Leaf Characteristics of Coffee (Coffea arabicaL.) Trees

Related articles

Top 10 largest coffee companies in Italy

IndexGeneral characteristics when decaffeinated The Roselius process The methods used to decaffeinate Process for decaffeination using ethyl acetate organic...

The influence of processing method on coffee flavor

IndexGeneral characteristics when decaffeinated The Roselius process The methods used to decaffeinate Process for decaffeination using ethyl acetate organic...

The taste of robusta coffee beans from a scientific perspective

IndexGeneral characteristics when decaffeinated The Roselius process The methods used to decaffeinate Process for decaffeination using ethyl acetate organic...

A detailed summary of Ethiopian coffee, the cradle of unique coffees

IndexGeneral characteristics when decaffeinated The Roselius process The methods used to decaffeinate Process for decaffeination using ethyl acetate organic...