Did you know that a naturally decaffeinated coffee bean doesn't exist. Similar to money, decaf coffee beans don't grow on trees. This fact prompts the natural question of “Well, then how is coffee decaffeinated?”
In this article, we'll be taking a look at how caffeine is removed from coffee and different processes that are available.
It was German merchant Ludwig Roselius that invented the first commercial decaffeination process in the beginning of the 20th Century. This was a discovery of chance stemming from a road accident that resulted in a load of coffee beans being soaked in sea water. To everyone's surprise, the sea water actually extracted caffeine from the beans without completely cancelling out the bean's flavor. What was by all definitions an unfortunate mishap on the road, ended up being a catalyst and inspiration for an entire industry of decaf coffee.
Keep in mind that because coffee beans are naturally caffeinated, no decaffeinated coffee is 100% caffeine free. According to the North American USDA, decaf coffee is that which had at least 97% of its caffeine removed. The European Union specification is stricter, stating that the beans have to be 99.9% caffeine-free in comparison with their total weight.
The Decaf Challenge
The big challenge of decaffeinating coffee is being able to remove caffeine while retaining the coffee's original flavor. Water, which is used in all decaf processes, doesn't just target caffeine but also the compounds responsible coffee's appealing smell and taste. For this reason, decaf coffee in the early days was often perceived as being “watered-down or diluted”. However, the ways in which coffee is decaffeinated has greatly evolved over the years and today, the option for great tasting decaf is a full-blown reality.
How is Coffee Decaffeinated – A Look at the Processes
When people ask the question “how is coffee decaffeinated”, there really is no singular answer since there are many different ways of decaffeinating your coffee. However, all of them will typically fall under the category of solvent or non-solvent.
Solvent decaffeination, as it's name suggests, involves the use of some kind of solvent either directly or indirectly as a means of preserving coffee flavor compounds. Solvents such as methylene chloride or ethyl acetate are often used in order to preserve the coffee bean's original attributes. For us science laymen, anything that has the word “chloride” may be an understandable cause for concern. However, methylene chloride has been subject to rigorous testing by the U.S. Food and Drug Administration (FDA) and has been determined to be safe. Known as the Methylene Chloride Decaf process (MCD), this method is thought by some in the industry to be more effective at preserving the taste of coffee. Ethyl Acetate which is commonly used in European decaffeination plants is regarded by many as a “more natural solvent” being that it's derived from a fruit.
Solvent decaffeination involves soaking coffee beans in near boiling water to remove both flavor and caffeine. The caffeine-laiden and flavored water is treated with a MC or ethyl acetate to essentially remove the caffeine from the water. The remaining water is now caffeine free but still contains the coffee's flavor compounds. The beans are then re-soaked in this water to reacquire their flavor while staying caffeine free.
Non-Solvent Decaffeination Method
Swiss Water Processing Method
The Swiss Water Processing Method (SWP) is often considered by many the healthiest and most natural way to decaffeinate coffee since it's never in contact with any solvents. Using the highly popular Swiss Water Processing method, coffee beans can be up to 99.9% decaffeinated without ever coming into contact with any chemicals. The process is quite ingenious. First, green coffee beans are soaked in water. The water removes both the caffeine and the natural flavor compounds. The water is transferred to another tank while being passed through a filter that's specially designed to remove the larger caffeine compounds, leaving the smaller flavor compounds unaffected. Basically, instead of using solvents like methlyene chloride to separate the caffeine, you're using a specialized filter to remove the caffeine. What you're now left with is a batch of caffeine-free and flavor-free coffee beans and a tank of caffeine-free but flavor-“FULL” water. The original batch of tasteless and caffeine-less coffee beans are tossed. The real value lies in the flavor-infused water which is then used to soak new coffee beans. Because the water already contains flavor compounds, it won't dissolve the flavor compounds in the coffee beans. You end up with decaffeinated coffee without a big flavor loss. Magic! Given this natural process, it's no surprise that this method is used almost exclusively for decaffeinating organic coffee.
The video below offers a great visual illustration for the Swiss Water Processing.
Finding the best tasting decaf coffee can sometimes be a challenge. But truly if you look for the Swiss Water Processing sign, you'll at least have peace of mind knowing your coffee was decaffeinated in one of the best and healthiest ways possible. Premium coffee brands such as Koa Coffee, Out of the Grey Coffee, and True Coffee Company offer an exquisite decaf brew that's made with the SWP method.
Carbon Dioxide Method
Another more recent non-solvent decaffeination method is known as the Carbon Dioxide (CO2) Method. It was developed by a scientist named Kurt Zosel from the Max Plank Institute. Unlike water, liquid CO2 acts selectively on caffeine which as we've mentioned is critical in the decaffeination process. This process involves storing water-soaked coffee beans in a sealed-container and pumping the container full of liquid CO2 at pressures of 1000lb/inch. This liquid CO2 plays the role of a solvent and removes the caffeine from the beans. Once the process is complete, the caffeine-infused CO2 is transferred to an absorption chamber where pressure is released allowing the CO2 to return to its original gaseous state and be reused for future batches. The Carbon Dioxide method is more involved and thus, more expensive than many other methods. Because of this, it's usually reserved for bulk quantities of commercial-grade coffee as opposed to small-batch exotic coffee.
Hopefully this article has helped answer the existential question of ‘how is coffee decaffeinated.' At the end of the day, coffee lovers aim for the ideal of great-tasting coffee that's free of harmful chemicals. The decaf industry has made major strides in this area and full-flavored decaf coffee is now no longer the exception. On a concluding note, if taste is your highest priority, it's worth noting that your selected roast will ultimately have more of an effect on flavor rather than the type of decaffeination process. Check out our article on tips for choosing the best decaf coffee.