Coffee contains thousands of compounds within its beans, of which caffeine is most famous.
Unfortunately, not everyone can take caffeine.
Some coffee lovers might experience stomach ulcers, heart palpitations, anxiety, heartburn and the likes.
Hence, the coffee industry has been developing and decaffeinating coffee since the 1980s.
How to Decaffeinate Coffee?
All coffee decaffeination processes undergo these 3 main steps:
- Raw green coffee is steamed and wetted to expand its volume and open up the pores or structure for easier extraction.
- A decaffeination agent is passed through the swollen green coffee to extract caffeine.
- Decaffeinated coffee beans are then dried using hot air.
2 major types of decaffeination processes
There are 2 general ways to decaffeinate coffee:
- Direct Decaffeination
As it’s name suggests, the decaffeination agent is in direct contact with the coffee beans during the decaffeination process.
After steaming, expanded coffee beans are rinsed with the decaffeination agent of choice (usually DCM, EA or CO2).
The extraction rate of caffeine of these solvents are rather slow.
Hence, the rinsing has to be repeated multiple times in order for at least 97% of the caffeine to be removed.
- Indirect Decaffeination
Unlike the direct method, the decaffeination agent does not come in contact with the coffee beans.
Instead, the water that was used to steam and soak the coffee beans will be decaffeinated.
The decaffeinated water is then re-used to soak the coffee beans and extract more caffeine through osmosis.
This process is repeated until the water has reached equilibrium and is no longer able to draw caffeine out of the beans.
4 agents commonly used in decaffeination
As mentioned above, there are 4 agents commonly used to extract caffeine:
- Dichloromethane (DCM),
- Ethyl Acetate (EA),
- Carbon Dioxide; supercritical (scCO2) and liquid (liCO2) states
Each solvent has its advantages, disadvantages as well as its optimal extraction conditions, here’s a quick summary:
|Dichloromethane (DCM)||Does not extract non-caffeine water soluble compounds||Touted to be unsafe by some.|
Might lead to environmental issues like the destruction of ozone layers, if DCM is released into the air during production.
|Ethyl Acetate (EA)||Does not extract non-caffeine water soluble compounds||Faces similar skeptism as DCM, even though it is a naturally occurring substance in ripening fruits.|
|Water||Generally easy for consumers to accept as a safe method of decaffeination||Non specific extraction of water soluble compounds in coffee.|
Higher cost due to additional steps required to prevent loss of non-caffeine compounds
|Carbon Dioxide||Highly specific extraction of caffeine||Higher cost due to equipment required for high pressure decaffeination.|
We’ll dive into the details of each of these 4 methods in this section.
Also known as Methylene Chloride.
Dichloromethane is a colorless liquid that gives off a feint sweet aroma at room temperature.
It is volatile, non flammable and has a low boiling point of 39.6°C.
The advantage of using DCM is that it does not extract water soluble non-caffeine compounds from the coffee beans.
Hence, there is lesser loss of water soluble compounds during this process.
The disadvantage of the DCM method is the debate and general skepticism on its safety.
DCM has been linked to carbon monoxide poisoning, cancer and heart attacks.
But rest assured, the level of DCM in decaffeinated coffee is almost negligible and is safe for consumption.
In addition, most of it would be removed during the roasting process of the decaffeinated green coffee beans due to its low boiling point.
Approved levels of DCM in decaffeinated coffee
The Agri-Food and Veterinary Authority of Singapore (AVA) only approves decaffeinated coffee products that contain less than 0.001% DCM.
You can read page 35 of AVA’s Food Regulation document for more.
And the U.S. Food and Drug Administration (FDA) has similar regulations.
Debates about the use of DCM
Despite the safety regulations, consumers remain wary of the safety of DCM.
And coffee decaffeination companies have used that fear to their advantages when marketing alternative decaffeination processes.
There have also reports that link the use of DCM in decaffeination to environmental issues like damaging the ozone layer. However, that claim would be highly dependent on how the decaffeinated coffee bean producers manage their waste gas output from decaffeination.
Ethyl Acetate (EA)
Ethyl Acetate is a colorless, sweet smelling liquid chemical.
It is highly flammable hence decaffeination facilities that use EA are required to take additional safety precautions.
EA has been proven to have low toxicity levels, however it has been shown to cause eye, nose and throat irritations at high concentrations.
EA decaffeinated coffee are sometimes referred to as ‘naturally decaffeinated’ coffee because ethyl acetate is naturally present in ripening fruits.
Approved levels of EA in decaffeinated coffee
EA is a substance that is ‘generally recognised as safe’ and is also being used as a flavoring agent and adjuvant.
There are no specific concentrations listed in the regulations for Ethyl Acetate.
However, good manufacturing practices (GMP*) that have been defined for the use of EA in food processes.
* According to AVA, GMP “means that the additive may be added to food at a quantity limited to the lowest possible level necessary to accomplish its desired effect”.
A note about organic solvent decaffeinated coffee
Both DCM and EA are non-water based organic solvents and their decaffeination processes ensure that water soluble flavor compounds within the coffee beans are not extracted along with caffeine.
However, it has been noted that organic solvent decaffeinated coffees often have an undesirable ‘cooked’ flavor.
Water decaffeination process removes the need for chemicals.
This is a summary of the process:
- Green coffee beans are expanded through steaming.
- Water used in step 1 is pass through activated charcoal that specifically removes caffeine.
- Water without caffeine is then used to wash and rinse green coffee beans again. More caffeine will be extracted to the water by osmosis.
- Steps 2 and 3 are repeated until 97% or more caffeine has been removed from coffee beans.
The disadvantage of using water is that other water soluble coffee compounds will also be extracted along with caffeine.
Hence, water based decaffeination usually makes use of:
- water pre-loaded with water soluble coffee compounds to reduce the extraction of non-caffeine compounds or,
- re-introduction of water soluble coffee compounds into the decaffeinated coffee beans after caffeine has been removed
Water decaffeination has been made popular by the Swiss Water coffee company, here’s their video explanation of how it works:
Many coffee drinkers have also highly recommended water decaffeinated coffee beans as being the cleanest, good tasting decaf coffee that loses the least amount of flavors.
Plus, the lack of chemical usage in the decaffeination process gives consumers peace of mind as well.
The CO2 decaffeination method was developed and patented in 1971;
In summary, after the coffee beans have been soaked and steamed, they will be transferred into containers and exposed to liquefied CO2 at high pressures which extracts caffeine specifically from the beans.
Carbon dioxide can be liquefied at high pressure and selectively removes caffeine from coffee beans.
This means that CO2 decaffeination does not face the issues of potential loss of non-caffeine flavor compounds from coffee beans.
However, the machinery required for this form of decaffeination is costly due to the high pressure requirement.
What is Decaffeinated Coffee?
Decaffeinated Coffee refers to coffee that have had majority of its caffeine removed;
- 97% of caffeine removed as per US standards
- 99.9% of caffeine removed as per EU standards
Yes, that means “caffeine-free” coffee is not 100% free of caffeine. You might want to note that there might be traces of caffeine present in decaffeinated coffee.
In Singapore, we follow the EU standards for decaffeinated coffee.
According to the Singapore Food Regulation, decaffeinated coffee refers to:
- coffee beans that contains less than 0.1% (w/w) anhydrous caffeine or,
- instant coffee that contains less than 0.3% (w/w) anhydrous caffeine
When was coffee first decaffeinated?
Ludwig Roselius, a merchant from Germany in 1903 invented the first commercial coffee decaffeination process. He went on to patent the process in 1906.
In those days, Roselius was decaffeinating coffee using benzene.
Later, benzene was labelled as a carcinogen (a substance capable of causing cancer) and was replaced by DCM and EA.
During which part of the process is coffee decaffeinated?
Coffee is decaffeinated after the drying and processing of the green coffee beans, before roasting is done.
Decaffeination can be done by specialized companies such as the Swiss Water Decaffeinated Coffee Company which then sells their decaf green coffee beans to smaller roasters, or done by large coffee suppliers who have in house coffee processing and roasting facilities.
Decaf coffee vs Regular coffee
As you’ve read above, decaffeination often leads to the loss of other compounds found in coffee as a ‘side effect’.
Here are the differences between decaffeinated coffee and regular coffee:
|Decaf Coffee||Regular Coffee|
|Roasting||Decaf coffee tends to react to roasting inconsistently, making it difficult for roasters to control the roasting process.||Quite Consistent within same batch of coffee|
|Appearance||Decaf coffee beans are usually yellowish and might contain dark spots.||Green|
|Loss of Mass||Decaf coffee beans usually have lesser water content. The decaffeination process might result in the lost of other coffee compounds as well.||Nil|
|Cost||Higher cost due to decaffeination process.||Nil|
Is decaf coffee safe to consume?
Most countries do regulate decaffeinated coffee products.
In Singapore, decaffeinated coffee has to:
- contain less than 0.001% DCM and,
- decaffeinated coffee beans have to contain less than 0.1% caffeine while decaffeinated instant coffee powder has to contain less than 0.3% caffeine.
How to choose decaffeinated coffee?
You now know the 4 main coffee decaffeination methods and that most decaffeinated coffee are safe for consumption.
So, how do you choose a good decaffeinated coffee?
Despite the debates on the pros and cons of each decaffeination methods, your choice of decaffeinated coffee should be based on your personal preference.
Where to buy decaf coffee in Singapore?
If taste is not that important, you can purchase decaf instant coffees at the supermarkets easily.
Otherwise, these are the only 2 coffee roasters in Singapore that provide decaf coffee beans:
- Common Man Coffee Roasters’ Decaf Colombia Coffee Beans
- The Providore’s Decaf Blend (roasted in Melbourne)
*These are not recommendations as we have not tasted these decaf coffees ourselves.
Do you serve Decaf Coffee?
Alliance Coffee’s mobile specialty coffee catering does not serve decaf coffee at the moment because we do not have the luxury of having 2 grinders at live events at the moment.
We do have non caffeinated drinks on our menu. Contact us for more.