Four Methods of Decaffeinating Coffee

White mug with Talking Crow Coffee Roasters roasted decaf beans inside

First let's start with some coffee bean basics.  There are some facts you should know, so grab a cup of coffee, sit down, and read on, my friend. 

FACT:  There are two main types of coffee beans - Arabica and Robusta.  Currently only Arabica beans are considered specialty coffee since Robusta is considered inferior.  Arabica beans produce a richer taste and have a better balance of sweet acidity, with more developed flavors.  Robusta by contrast has stronger, harsher, full bodied flavors with a more bitter taste.  Arabica beans are generally more commonly used, however big corporate coffee companies often use a mix of both.

FACT:  Raw Arabica beans have 1.2% caffeine.  Raw Robusta has nearly double the amount with 2.2% caffeine.  Congruently, after roasting Robusta beans contain more caffeine than Arabica beans.  

FACT:  The amount of caffeine in a single roasted Arabica bean is about six milligrams.  A roasted Robusta bean has 10 milligrams.

FACT:  Contrary to popular belief- that light roasts contain more caffeine than dark – caffeine levels remain stable through the roasting process, in other words coffee beans contain a certain amount of caffeine and that level of caffeine does not change with level of roasting.1 

Maybe you love coffee for the morning pep in your step, but perhaps, you are like me and need to avoid caffeine.  Let's talk about removing that caffeine or better known as the decaffeination process.  There are some facts you should know.

FACT:  There are no naturally occurring decaffeinated coffee beans, which means that decaf coffee needs to be created by physically removing the caffeine from green coffee seeds.

FACT:  All coffee is green (unroasted) when decaffeinated and with each method the beans are first soaked in water allowing the beans to swell for easier caffeine removal.

FACT: There are two basic ways beans are decaffeinated - either with a solvent or without. 

In the solvent method either methylene chloride (aka MC) or ethyl acetate (EA) are used.  In the non-solvent method either CO₂ or water is used. 


Methylene Chloride or dichloromethane (in Europe) is used in various industrial processes such as paint stripping and removal, pharmaceutical manufacturing, and metal cleaning/degreasing.  The FDA has determined that any health risk associated with its use in decaffeination is low because it is used in such small amounts, and some think it is unlikely that any traces of the chemical remain after roasting, however, those presumptions have not been proven.  Furthermore, the allowed amount by the FDA is 10 parts per million residual so there can potentially be trace amounts remaining on the beans.  For those people sensitive to chemicals, it is something to consider. This method is most commonly used in Europe where most decaffeination is done.   

Ethyl Acetate is often labeled as "natural"  Ethanol is produced naturally in the fermentation of fruit and wine. Interestingly, the wine industry considers large amounts of ethanol in wine to be a contaminate.  Ethyl Acetate is made synthetically by reacting acetic acid with ethanol (the part found in nature) in the presence of a sulfuric acid catalyst. This same chemical in large amounts is commonly used in glues and nail polish removers.3  The levels of ethlyl acetate used to decaffeinate coffee are GRAS (generally regarded as safe) by the FDA.

The Method

In both of the solvent methods caffeine can be extracted both indirectly and/or directly.  In the direct method the beans are, you guessed it, directly soaked and rinsed in the solvent.  Once the caffeine has completely migrated into the solvent and out of the beans, it is rinsed to remove any residual solvent.

In the indirect-solvent method the coffee beans are soaked in very hot water for several hours, which extracts the caffeine as well as other flavor elements and oils from the beans.  The water is then separated and transferred to another tank where the beans are washed for about 10 hours with either methylene chloride or ethyl acetate. The molecules of the chemical solvent selectively bond with the molecules of caffeine and the resulting mixture is then heated to evaporate the solvent and caffeine.  Lastly, the beans are reintroduced to the liquid to reabsorb most of the coffee oils and flavor elements.  The decaffeinated beans from both the MC and EA  - direct and indirect methods are 97% caffeine free.4


CO (Carbon Dioxide) Method was developed fairly recently by Kurt Zosel.  In this process, the beans are first soaked with water, then placed in a stainless steel extraction vessel. The extractor is then sealed and liquid CO2 is forced into the coffee at high pressure (1,000 psi).  The CO2 acts as the solvent to dissolve and draw the caffeine from the coffee beans, leaving the larger-molecule flavor components behind. The caffeine laden CO2 is then transferred to a separate "absorption chamber". Here the pressure is released and the COreturns to its gaseous state, leaving the caffeine behind. The caffeine free CO2 gas is pumped back into a pressurized container for reuse.  So basically, this method uses liquid CO2 in place of chemical solvents which acts selectively on the caffeine, releasing only the caffeine molecule and nothing else. This chemical-free method results in coffee that is 97% caffeine free.5

Swiss Water Process (SWP) -  Once the green coffee (unroasted) is received at the Swiss Water facility in Vancouver, British Columbia it is hydrated with pure, local water.  Their proprietary Green Coffee Extract (GCE) is introduced to the water-soaked beans.  This GCE naturally displaces the caffeine from the beans into the solution through the process known as diffusion (osmosis).  The caffeine flows out of the beans until the ratio of caffeine in the GCE and in the coffee reach an equilibrium.  The caffeinated GCE then passes through a series of caffeine-specific carbon filters until all the caffeine is trapped and separated from the extract - without removing any of the flavor compounds. The new caffeine-free GCE is used to remove more caffeine from the coffee, repeating the process until it is 99.9% caffeine-free.  This method is certified organic.6                                   

(Side Note:  Swiss Water derives its name not from the use of water from Switzerland, but the original method of using water and osmosis that was pioneered in Switzerland in 1933.)

Mountain Water Process (MWP) is done by the Descamex Company located in Mexico.  This method is similar in concept to the Swiss Water Process in that it uses pure local water (in this case from the glaciers of mountain volcano Pico de Orizaba and carbon filters to extract the caffeine.  This method is also certified organic, however is only 97.5% caffeine free.7

I'm sure you are familiar with our story and why decaf is important to us, but just in case you aren't, you can read about it here.   Since we are micro roasters of specialty coffee with a focus on decaf we take decaf seriously and have chosen to use only coffee that has been decaffeinated by the Swiss Water Process.  The blue Swiss Water logo on all our decaf bags is your guarantee that it is chemical free and 99.9% caffeine free. 

Decaf done right (and by that we mean both the decaf process and the roasting) tastes absolutely amazing!  In fact, it's our goal to roast in such a way that you cannot tell the difference (minus the buzz, of course.)

Give ours a try, won’t you.  We think you’ll be amazed!  It's coffee worth talking about!   

Coffee is for everyone - caffeine isn't. 

all day.   every day.   coffee you love.



Information gathered from the following websites.







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