The Decaffeination Process

How Does Decaffeination Actually Work?

All decaffeination starts with the same fundamental challenge: remove the caffeine from a green coffee bean without stripping away the flavour, aroma, and character that makes a great cup worth drinking. The process involves opening the bean's structure, drawing out the caffeine, and then carefully drying the bean back to its natural state.

There are four main methods used today. At Decaffeinated in Canada, we only carry coffees processed using natural decaffeination methods. That means you will never find the direct solvent method in our shop, but we've included it here so you understand what sets the others apart.

 

Direct Solvent Method

This would be the first method for decaffeination completed in Germany in the early 1900s. Commonly called the European Method. This method involves soaking green coffee beans in a solvent, usually methylene chloride (dichloromethane). These solvents bond with the caffeine molecules, extracting them from the beans. After a period of soaking, the beans are dried, and residual solvents are removed during drying.  

This infographic is from the National Coffee Association showing the European Method. 

 https://www.ncausa.org/Decaffeinated-Coffee

 

Swiss Water Process

In this method, the green coffee beans are soaked in water to expand the pores. It is placed into a caffeine-lean green coffee extract (GCE). Since the other water-soluble parts of the green coffee bean are in the GCE, the caffeine is the only part removed. The resulting water is a caffeine-rich GCE, which goes through a filtration process to remove the caffeine return to a caffeine-lean GCE. This process is repeated until the green beans are 99.9% caffeine-free and sent to be dried.

This infographic is from the Swiss Water Process explaining their decaffeination process.  

 https://www.swisswater.com/pages/coffee-decaffeination-process

 

Carbon Dioxide (CO2) Method

This is also called supercritical CO2 or subcritical CO2.  In this method, green coffee beans are steamed swelling the bean and opening the pores. The beans are then placed in contact with a CO2 mixture, in which the caffeine dissolves in the CO2 and other compounds stay with the bean. The CO2 mixture at the subcritical or supercritical state is highly selective at only extracting the caffeine. The CO2 mixture with the caffeine is sent to decrease the pressure where the CO2 goes back to a gas state and the caffeine is extracted. The CO2 gas is then compressed again to go into a liquid state ready to extract caffeine. Once the beans have removed the caffeine, they are dried to return to their natural state. 

Below is an infographic from Belco on an article about the CR3 plant in Germany which does CO2 decaffeination. 

Sugar Cane Process 

This is a common process to see in decaffeinated coffee beans lately. The sugar cane process uses a natural source of ethyl acetate from organic sugar cane.  The green beans are soaked in hot water to expand and open up the pores.  This is when the sugar cane derived from ethyl acetate is soaked with the beans extracting the caffeine. When the process is done, steam is used to remove residual ethyl acetate from the bean.  Then the beans go through a drying process to return the beans to their natural state. 

Below is an infographic from Decafesol in Colombia showing the sugar cane decaffeination process.  

 https://www.descafecol.com/en/decaffeinated-products/