This is one of the most searched coffee-related questions on the web:
How is coffee decaffeinated?
Well, in simple terms, it means that the caffeine has been removed from the coffee.
The more detailed answer is that decaffeination is the act of removing caffeine from coffee beans, cocoa, tea leaves and other caffeine-containing materials.
There are actually three main methods of decaffeination: the Swiss Water Process, the CO2 Process, the Methylene Chloride Process and the Ethyl Acetate Process.
Let’s go through each decaffeination process in turn:
1) The Swiss Water Decaf Process (SWP)
Developed in Switzerland in the 1980s, the Swiss Water Process is a chemical free water process. The green (raw) coffee beans are immersed in water to extract the caffeine using water saturated with desirable coffee components, thereby reducing the extraction of coffee oils and flavours during the decaffeination process.
This means the caffeine is extracted, but not the flavour. This steaming process takes 8 to 10 hours and involves moving the decaf batch into various baths of steam. Decadent Decaf only uses premium, high-grade coffee beans decaffeinated using the Swiss Water Process.
2) The CO2 Decaf Process
The CO2 method was developed by Dr. Kurt Zosel of the Max Planck Institute. In science-speak, this is called supercritical fluid extraction. Basically, the process starts with the beans being immersed in carbon dioxide (same gas as in sparkling water) for around 10 hours.
Some roasters call it the Sparkling Water Decaf Process, but we think that this is not accurate and they should use the correct term CO2 Process. After a thorough soaking, the pressurized CO2 containing dissolved caffeine is removed from the chamber which is returned to atmospheric pressure, allowing the CO2 to evaporate. This allows the caffeine to be removed using charcoal filters.
3) Methylene Chloride Decaffeinated Coffee Process (MCP)
Methylene Chloride solvent decaffeination is the old fashioned way to decaffeinate coffee and it's still how the vast majority of coffee is decaffeinated globally. When you drink decaffeinated instant coffee, it will almost certainly be decaffeinated using the Methylene Chloride solvent process.
Likewise, if there's no mention of how the roast coffee was decaffeinated on the packet, again, it's almost certain to be MCP.
Methylene Chloride is a colourless chemical solvent in liquid form with a slightly sweet aroma with a a boiling point of 104°F. It is a chemical solvent with multiple uses including paint remover and hair spray.
Methylene Chloride decaffeinated coffee is manufactured in the following way:
First, the coffee beans are treated with steam to draw the caffeine from the inner coffee bean to the outer surface area of the bean.
Methylene Chloride is then applied directly to the beans. As a chemical solvent, MC removes the caffeine.
Then steam is applied to the coffee beans again to drive out residual solvent.
Finally, the beans are dried and roasted, which removes any further residues of the chemical solvent.
Any amounts of methylene chloride left in brewed coffee would be less than one part per million.
4) Ethyl Acetate Decaffeinated Coffee Process (EA)
An increasingly popular newish decaffeination process is the Ethyl Acetate (EA) decaf process, often called "Sugar Cane Decaf", and, simply put, the Ethyl Acetate decaf method uses a natural solvent - Ethyl Acetate to decaffeinate the coffee beans.
Ethyl acetate is seen by some to be more “natural” than other chemicals since it exists naturally in minute quantities in ripening vegetation, such as sugar cane, apples and blackberries.
Therefore, since this solvent occurs in nature, it's often marketed as “naturally” decaffeinated or as "Sugar Cane Decaf" since Ethyl Acetate is usually sourced as a by-product from the fermentation of sugar cane during the manufacture of processed sugar.
But, according to various scientific sources (source: Coffee Confidential), because of the cost of gathering natural ethyl acetate, the chemical used for decaffeination is often actually synthetic.
This is because Ethyl acetate can be more affordably sourced and manufactured using ethyl alcohol and acetic acid, both of which are normally produced from natural ingredients and petroleum derivatives.
First, the green coffee beans are first soaked in water and then steamed in order to expand the cells of the bean. Then, the green beans are then soaked and washed in Ethyl Acetate solution, which attracts and removes the caffeine. After the Ethyl Acetate wash, the coffee is then rinsed, dried and packed for shipping.
IMPORTANT: This information is intended to support, not replace, discussion with your doctor or healthcare professionals. Nothing in the content or products should be considered, or used as a substitute for, medical advice, diagnosis or treatment. You should always talk to your health care provider for diagnosis and treatment, including your specific medical needs.