4 Methods for Making Decaffeinated Coffee, Explained

Koffee Kult decaf coffee

by Matt Gibson

There are four major decaffeination methods that are used to make decaf coffee today. These methods are known as the Direct Solvent Process, the Indirect Solvent Process, the Swiss Water Process, and the Carbon Dioxide Process. 

Each of these decaffeination methods begin in a similar fashion, by using green coffee beans, and extracting the caffeine before the drying and roasting process begins. As caffeine is a water soluble compound, it makes sense that the first step in the extraction process is to soak the green coffee beans in order to leach out the caffeine. 

The problem which then arises for coffee makers, is that caffeine is not the only water soluble compound in coffee. In fact, there are over 1,000 water soluble compounds in coffee beans, many of which are responsible for its robust, and complex flavors, as you know from brewing the roasted grounds. 

Water is not a selective solvent, as it will remove more than just the caffeine from the green coffee beans. Therefore, each of the caffeine removal processes use a selective solvent to draw out the caffeine without removing too many of the other important compounds so as to limit alterations and avoid diminishing the flavor and quality of the beans in the process. 

But before we take a deep dive into the different decaffeination procedures, let’s take a look at how caffeine was discovered, reveal why caffeine gets such a bad wrap, and then, let’s figure out why people around the world started to demand a caffeine-free version of the popular beverage in the first place. 

A Brief History of Caffeine 

In 1820, Johann Wolfgang von Goethe, a German scientist, playwright, poet, and all-around renaissance man was once given a case of coffee beans, which he asked his chemist friend, Friedlieb Ferdinand Runge to analyze. 

Goethe knew Runge was the man for the job due to his insightful analysis of Belladonna. Runge was able to isolate and analyze the various compounds in the poisonous blooms, and upon doing so, discovered some very important and unique substances, such as a potent poison, and a compound that causes dilated pupils. Goethe figured, if this guy can get so much knowledge and value out of a toxic weed, he will likely demystify and uncover a great deal about the coffee bean. Upon inspecting the beans, Runge discovered the caffeine compound, and was able to isolate it for further research. The love/hate relationship between caffeine and humanity officially began. The chemist had no idea that the compound he had found would go on to become the world’s most widely consumed psychoactive drugs.Technically, folks had been chugging coffee for decades, and were already quite familiar with the effects of caffeine. They just didn’t know what the substance was called, or how it affected their mood and energy level.

Caffeine’s Negative Press Doesn’t Seem To Affect Demand 

Throughout thousands of years of coffee and tea consumption, caffeine has repeatedly been shown in a negative light, using scientific studies and anti-joe propaganda. But in actuality, caffeine is not really that harmful, unless you are consuming it in massive quantities. Sure, a strong cup of coffee can be very stimulating, and can even cause jitters, and a mid afternoon crash (which is why you always need that afternoon pick-me-up). But as far as the science is concerned, a little coffee is actually q uite good for you, and can be used to help you stay awake, to focus and perform, to improve your endurance, and to boost your mood. 

Considered a stimulant, caffeine is not only found in coffee, but in a wide range of other foods and beverages, including tea, and even chocolate. Coffee is a morning staple in many parts of the world, and is commonly used to provide an energizing boost to help people jump start their day. And despite caffeine’s noted bad reputation in this week’s news, it still remains one of the most popular beverages in the world and a hot commodity on the world market. 

Why Decaf?

12% of the coffee consumption in the world is decaffeinated coffee. The demand arose due to the desire to drink coffee without the extra energy. For example, when a craving arises for coffee in the evening time, decaf coffee can be substituted for regular coffee so as not to disturb sleep cycles or cause insomnia. Some people are more sensitive to caffeine than others are. One or two cups of joe in the morning is like a breath of fresh air for coffee drinkers, and it’s exactly the amount of caffeine they require to jump start their day, However, even seasoned coffee enthusiasts can suffer from an edgy, jittery disposition when too much coffee has been consumed. If you have heart health issues, avoiding excessive amounts of caffeine is a very serious matter. 

For those who truly love the taste, aroma, and ritual of coffee, kicking the habit is entirely out of the question. However, some decaf coffees can be a halfway decent substitute for the real thing in a pinch. There is a time and a place for decaf coffee. Never, and in the trash. I kid, but really, decaf is never as good as regular roasts, and after leaching out the caffeine, and (depending on the process used) a whole bunch of other materials responsible for coffee’s balanced, complex, and robust flavors. If you love the taste of coffee enough that you find yourself wishing you could drink another coffee during the evening solely for enjoyment, but you worry that drinking coffee late in the day could disrupt your sleep cycle. 

A Brief History of Decaf Coffee

Convinced that his father died due to drinking too much coffee, a German salesman named Ludwig Roselius discovered a method of removing the caffeine from the green coffee beans before roasting. He believed that the caffeine from coffee was the toxic reaper that ended his father’s life. Unfortunately, Roselius used Benzene to extract the caffeine, which is actually far more poisonous than caffeine could ever be, and is recognized as a carcinogen by the FDA.

It is more than a little bit ironic that Roeselius removed the caffeine from coffee beans because he believed that it was poisonous, while the process that he created to remove the caffeine, ended up using a cancer-causing compound. A fine example of the fickle finger of fate’s excellent sense of humor. 

For years, Roselius’s carcinogenic decaf blend was served piping hot to decaf drinkers and was the only non-caffeinated option on the market. However, all good (and bad, in this case) things must come to an end, and fortunately, Roselius’s dangerous decaf experiment was eventually replaced. 

Unfortunately, things didn’t get any easier for decaf drinkers for a while, as it actually took coffee roasting companies a good bit of trial and error in using solvents to remove the caffeine from their products before much safer practices were put to use in the industry. In fact. Roselius wasn’t the only one who unknowingly used a carcinogen to take the zing out of his coffee beans. Three other toxic compounds (including chloroform) were once used as solvents to make decaf coffee. 

Nowadays, there are four decaffeination methods used regularly. Two of these methods still use chemical solvents to remove the caffeine molecules (ethyl acetate and methylene chloride), though their processes have been deemed safe by the FDA and only allow trace amounts of chemical compounds in their products. 

Despite their chemical nature, the two solvents which are used in modern decaffeination processes are actually quite safe. Applied either directly, or indirectly to the coffee cherries, methylene chloride and ethyl acetate are both non-harmful to humans. Methylene chloride is considered safe by the FDA for use in decaffeination processes, and only trace amounts are allowable in the final product, but the compound actually evaporates at temperatures over 100 degrees Fahrenheit, so there’s a slim chance of any finding its way into a barista bar in your neighborhood. Ethyl acetate is actually considered to be an all-natural way of decaffeinating coffee, as the solvents’ primary ingredients occur naturally in several fruits and berries. 

The two alternative methods use activated charcoal, and pressurized CO2.  to complete the same task. The Swiss Water Process (invented in Switzerland and adopted by Canada) is the most commonly used method for organic coffee makers. The Swiss Water decaffeination technique uses activated charcoal, which the company’s website refers to as a, “proprietary carbon filter system,” to extract the majority of the caffeine from the green coffee beans prior to roasting. The Carbon Dioxide Process uses advancements in modern science to create environments of pressurized carbon dioxide which can remove only the caffeine from coffee cherries, allowing all the other molecules that the other processes extract and then try to re-inject into the beans.    

METHOD 1 – Direct Solvent Process

The Direct Solvent method can be performed using either methylene chloride or ethyl acetate. The green coffee cherries are first prepared by soaking in water held at temperatures just below the boiling point. Soaking the cherries in hot water makes them more sponge-like, and able to absorb more of the chemical solvents. 

After their hot tub session, the cherries are then rinsed continuously with one of the two solvents for 10 to 12 hours. Next, the cherries are thoroughly rinsed to remove any traces of residual solvent. Afterwards, they are then allowed to dry, which turns them into beans, which are finally ready to be roasted. 

METHOD 2 – Indirect Solvent Process

The indirect solvent method also begins with a hot water bath. However, in this process, they are being soaked in order to extract the caffeine, which is water soluble. The caffeine, as well as many other flavor agents, compounds, oils and sugars, are all separated from the coffee cherries and moved to a holding tank. Now isolated, the concentrate can be mixed with a solvent solution. Once the solvent bonds to the caffeine molecules, the mixture can be heated, which causes the solvent, as well as the caffeine, to evaporate entirely. 

After the caffeine and the solvent has been removed, the beans can be reintroduced to the concentrate in an attempt to restore as much of the essential compounds that would have otherwise been lost by the extraction. The indirect solvent process removes the caffeine from coffee cherries without requiring the solvent to ever come in direct contact with the cherries themselves. Science is fun.

METHOD 3 – Swiss Water Process

Like the other decaffeination methods, the first step of the Swiss Water Process involves soaking the green coffee cherries in a hot water bath in order to create what the Swiss Water company webpage refers to as GCE, or Green Coffee Extract, which is made up of all of the water soluble compounds found in green coffee cherries. First, the cherries are cleaned and pre-soaked to prepare them for extraction by removing any dust particles, as well as the outermost layer of skin, called the silverskin. 

Once the cherries are prepped, the GCE is extracted. Then, the cherries take a long soak in the GCE while the caffeine is being slowly extracted by allowing the liquid to filter through various layers of activated charcoal. After all of the caffeine is removed and is trapped in the, “carbon filtration system,” the carbon is passed through a furnace that easily evaporates all of the caffeine molecules so that the charcoal filters can be reused in future decaffeination processes. Throughout the entire process, the GCE is constantly being refreshed and refined, and it can be reused for multiple batches of decaf coffee making. After the coffee cherries are stripped of their caffeine, they are then dried, roasted, packaged, and sent out to market. The majority of organic coffee roasters use the Swiss Water Process to make their decaf blends, as it is completely natural and relies on only natural ingredients. 

METHOD 4 – Carbon Dioxide Process

The Carbon Dioxide Process is the new kid on the decaf coffee method circuit, and though it is listed last in our decaf method feature, it is certainly not the least by any measure. This isn’t some simple solvent wash or filtration technique. No, this is real technical sciency stuff. Let’s dive in, shall we? 

The CO2 Process is also known as the Supercritical Carbon Dioxide Method, or the Liquid Carbon Dioxide Method. It was developed by super scientist and fellow of the Max Plank Institute, Kurt Zosel. Instead of solvents, liquid CO2 and high pressure environments are combined to separate and isolate only the caffeine molecules from the coffee cherries. 

The carbon dioxide absorbs the caffeine and is then moved to an isolation chamber, where it is heated to temperatures which evaporate the caffeine molecules. This process cleans the carbon dioxide gas so that it can be used again to process more coffee into decaf. 

It’s unfortunate that such incredible techniques are only used to produce big budget brand grocery store blends and lower quality coffees that are produced in bulk. This is due to the cost of the processing. Techy science is for deep pocketbooks. If only specialty coffees made their decaf roasts using this method, there might be some better decaf options on the shelves, as this method is definitely superior at preserving the taste of the original coffee cherries while removing the caffeine. 

Why Is It So Hard To Make Good Decaf Coffee? 

It really is a tall task to create a decent decaf, much less, a spectacular decaf coffee. This is because three of the four decaffeination methods involve removing all the water soluble elements of the cherries in order to get the caffeine isolated and remove it. Coffee makers then endure the struggle of trying to replace those missing compounds to restore the flavor of the original cherries. 

Does Decaf Coffee Have A Weaker Flavor Than Regular Coffee? 

Some methods do a better job than others at this tough task, however, decaf coffee will nearly always fall short of regular coffee when it comes to the depth and complexity of the flavor. Once all of the water soluble elements are removed from the cherries, there is no way to get them all back in place before roasting. It’s just impossible. The cherries have basically been pre-brewed before they are ever roasted. It just makes sense that they would be significantly weaker and less interesting on your palate. 

Which Methods Are All-Natural Processes?

Though both the Direct and Indirect Solvent methods use chemical solvents, one of the two solvents that is used for the task occurs naturally in several fruits and berries. The other two methods, which use charcoal and carbon dioxide, are also all-natural processes. 

Which Decaf Coffee Process Is Better?

Each of the four methods of decaffeination have their own strengths and weaknesses, and it is up to you to decide which you like the best. However, in terms of preserving the taste of the original coffee cherries, you can’t beat the Carbon Dioxide Method. The Swiss Water technique uses a vast amount of care and attention to reinject the lost compounds back into the coffee cherries prior to roasting. The two methods which rely on chemical solvents to decaffeinate coffee are both reliable, safe, and produce a fairly consistent, but somewhat weaker coffee than non-decaffeinated roasts, but they do a pretty good job of mimicking the pick-me-up cup of joe that you grew up on, minus the caffeine of course. 

What’s your favorite decaffeinated coffee and which of the four methods does it use? Can you tell the difference between your favorite brand and other popular options? How many different decaf coffees did you have to try before you purchased one that you truly enjoyed. Let us know in the comment section, and keep on brewing. 

Learn More About Decaf Coffee

https://www.bbc.com/future/article/20180917-how-do-you-decaffeinate-coffee

https://www.britannica.com/story/how-is-coffee-decaffeinated

https://coffeeconfidential.org/health/decaffeination/

https://www.swisswater.com/pages/choice

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