How is coffee decaffeinated?
There are three main methods of decaffeination:
- The Swiss Water Decaffeination Process
- The CO2 Decaffeination Process
- The Methylene Chloride Decaffeination Process
- The Ethyl Acetate Decaffeination Process
The Swiss Water Process
Decadent Decaf only uses Swiss Water Process decaffeinated coffee beans, which are certified 99.9% caffeine free and uses water (no yukky chemicals whatsoever) to decaffeinate the beans.
Developed in Switzerland in the 1980s, the Swiss Water Process is a chemical free 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. Currently, Decadent Decaf only uses premium, high-grade coffee beans decaffeinated using the Swiss Water Process.
You can find out more about the Swiss Water Decaf Process in detail here on our Swiss Water Decaf Page.
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. Again, this process avoids the use of any harmful substances and Decadent Decaf is investigating sourcing premium, great tasting beans using the CO2 Process for the future.
In environmental terms, the CO2 used is in a permanent cycle, rather than vented to atmosphere – there will be some further off-gassing when the beans are removed from the system (no process being perfect), but for the most part, it’s a closed system, which is good news for the environment.
Methylene Chloride Decaf 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.
But what is it?
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.
The method of solvent decaffeination is as follows:
- 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 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.
Ethyl Acetate Decaf Process (EA)
An increasingly popular newish decaffeination process is the Ethyl Acetate (EA) decaf process, often called "Sugar Cane Decaf", but what is the EA decaf coffee process all about?
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.
What is the scientific process for Ethyl Acetate decaffeination?
i) The green beans are first soaked in water and then steamed in order to expand the cells of the bean.
ii) The green beans are then soaked and washed in Ethyl Acetate solution, which attracts and removes the caffeine
iii) After the Ethyl Acetate wash, the coffee is then rinsed, dried and packed for shipping.