How is coffee decaffeinated?

This article is a guest post written by John Bedford, founder of Viva Flavor, a blog dedicated to helping budding baristas develop their love of coffee.


Some people naturally have a very low tolerance to caffeine and are more susceptible to some of its more infamous side effects, such as insomnia and anxiety. 


Others still might need to significantly reduce their caffeine intake for health reasons, or because of pregnancy, for example.


Even those of us with a hearty appetite for the stuff can benefit from toning down our intake as the day wears on and bedtime approaches!


The good news is that you don't have to compromise on flavor too much if you want to reduce the amount of caffeine you're drinking every day. 


Decaf's come along way over the last few decades, but how exactly do they go about eliminating such an integral part of the coffee bean?


How is coffee decaffeinated?


There are four main methods used to decaffeinate coffee.


The tricky thing in each case is that there are many hundreds of different compounds locked within a coffee bean. 


The challenge is to remove the caffeine without also eliminating the delicate chemical dance that provides the bean with its aroma and – eventual – flavor.


#1 The Solvent Method


This is one of the oldest known methods for decaffeinating coffee. As the name suggests, though, it makes use of additional chemicals during the process.


That process begins with steaming of the beans, after which they're soaked in a solvent that's designed specifically to absorb the caffeine compounds.


Once this soaking process has concluded, the beans are steamed again to remove traces of the solvent. Finally, the beans are dried thoroughly and then roasted.


The use of solvents has a controversial history, however. 


One of the earliest chemicals used in this process – trichloroethylene – was cited by the National Cancer Institute as a likely cause of the disease towards the middle of the 1970s.


Although it's far from certain how much of the solvent remains once the second steaming process has finished, this naturally caused a great deal of alarm.


In response, the industry developed two new solvents: methylene chloride and ethyl acetate.


The former is not currently cited as having any adverse health implications and is now commonly used.


As for the latter, it's derived from fruit, and so is almost certainly benign. With that said, though, some feel it inevitably affects the final flavor of the coffee, and so it introduces its own problems.


Given the history of this particular decaffeination method, it's understandable that many consumers prefer to avoid coffee that's been prepared this way altogether.


#2 The Indirect Solvent Method


This method is a slight variation on the first method and mostly keeps the beans at arms' length from whichever solvent is being used.


Once the beans have been soaked in hot water for a few h

ours, that water is then added to another vessel.


A solvent is then added to the water, which binds with the caffeine that's been extracted. The end result is a substance that can be easily removed from the surface of the water and disposed of.


Crucially, the next stage sees that caffeine-free water (which still contains the various oils and compounds from the coffee bean) added back to the first vessel.


Those elements are then absorbed back into the beans before they're dried out and readied for roasting.


#3 The Swiss Water Method


The Swiss Water approach to decaffeinating coffee uses no solvents whatsoever and produces, in our opinion, the best results.


First of all, an initial batch of beans is soaked in hot water. This naturally extracts some of the caffeine from the beans, but it also strips out many of the compounds that give the bean its flavor potential.


Rather cleverly though, that flavor is maintained across the rest of the production line using a two-step process. 


First of all, the wastewater is percolated through activated charcoal. That removes all of the caffeine from the solution, but not the oils and sugars. 


The end result is something known as Green Coffee Extract. This extract is then added to another batch of beans, which goes through the same soaking process. 


The difference this time around, however, is that the beans are swimming in all those aromatic compounds.


The eventual result? A batch of decaffeinated coffee beans that hasn't had its flavor compromised.


(This a very simple overview of how things work, incidentally. The actual process involves many tanks recycling the extract continuously!)


#4 The Supercritical Carbon Dioxide Method


A relatively recent development is known as the supercritical CO2 decaffeination method. Again, it eschews the use of solvents altogether in favor of a more natural process.


Once the beans have been soaked in water, they're then placed in extraction vessels, ready for the next stage.


Inside those vessels, liquid CO2 is pumped through at an exceptionally high temperature and pressure. 


This supercharged CO2 absorbs both the caffeine and a percentage of the water.


The entire process can take several hours, and it's the most expensive way of going about all this. 


Once it's finished the beans are simply removed and dried out. Once dry, they're ready for roasting.


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Now you know how coffee loses its caffeine kick. Viva Flavor has a dedicated coffee bean guide if you'd like to learn more about the history of the bean, and the different types that are grown around the world.


For a delicious cup of decaf coffee at home, we highly recommend our Colombian Swiss Water Process Medium Roast. 

 

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