Learn About Decaf Processing

In Search of Lost Caffeine 

Caffeine may be the boost that many coffee drinkers are looking for, but many others–as much as 20% of coffee drinkers–are actively avoiding it, opting instead for decaffeinated coffee. This brand of coffee drinker is seeking the great taste of coffee without any of the boom-and-bust experience of caffeine. 

The Basics 

Before we get into the nitty-gritty, let’s cover some of the basics. The major challenge in decaffeination is to separate the caffeine without also removing many of the flavor compounds that make coffee so delicious. All beans are decaffeinated as green beans and because caffeine is water soluble, every processing method uses water. 

Decaffeinated coffees are not 100% caffeine-free. Most decafs have 2-3% of natural caffeine remaining, usually between 1 and 7 milligrams per cup. 

Decaffeinated coffee is still hotly contested over taste and appeal. While some swear by decaf coffee, others abhor it. We’re not here to tell you what you or your customers like, but we can tell you a bit about some of the lesser known aspects of decaffeinated coffee. 

Health Facts 

While caffeinated coffee is often touted for its antioxidant properties as well as other lesser-known benefits such as reducing Parkinson’s tremors in men, decaffeinated coffee has been linked with some negative health effects. A 2005 study found that decaf drinkers had higher levels of certain cholesterols and other early markers of heart disease. At the same time, however, some studies have found that the benefits of decaffeinated coffee are similar to that caffeinated coffee in areas such as reducing risk of type 2 diabetes. 

Taste 

There’s no definitive guide on the best decaffeination method for preserving taste. Given the huge number of flavor compounds in coffee, trying to extract just caffeine is extremely difficult. One of the side effects of decaffeination is that the processes cause the bean to swell and the cells to open, creating a looser structure in the bean. (This is also why you won’t hear a ‘crack’ during roasting: because the moisture escapes much more easily through the loosened structures). These looser structures may allow more flavor compounds to evaporate during roasting and lead to a different, or reduced, flavor profile. 

Environmental Impacts 

The jury is still out on the exact environmental impacts of decaffeinated coffee methods. However, considering the high water usage of coffee in general (it takes about 37 gallons of water to produce one cup of coffee) adding another process like decaffeination that’s undoubtedly water-intensive will add to the environmental footprint of coffee drinking. 

The Methods  

Ethyl Acetate (EA)  

Ethyl acetate is an ester that occurs naturally in fruits and vegetables. Because it is naturally occuring, the EA process can be labeled as “naturally decaffeinated.” EA process is relatively simple. The coffee beans are moistened with water and EA is circulated throughout. The EA binds with the caffeine in the bean and extract it while leaving most of the other flavor compounds. After the desired caffeine level is reached, the EA residue on the beans is removed by steaming them. 

Methylene Chloride (MC)  

The methylene chloride decaffeination process is the same as EA processing with one central difference. Because MC is not naturally occurring in plants, the resulting decaffeinated coffee cannot be labeled as “naturally decaffeinated.” That being said,  MC was determined by several health organizations not to be a health risk in amounts under 10 parts per million (PPM). In MC decaffeinated coffee, MC remains in amounts under 1 PPM. Further, MC is highly volatile and evaporates at 40 degrees C. Considering the high temperatures of roasting (about 204 degrees C) and brewing (about 93 degrees C) it is highly unlikely that any MC remains in the final beverage. 

Water Process (WP)  

Water Processing is known as a decaffeination method free of added chemicals that uses only the purest water. The most common producer of water process is Swiss Water. 

The process begins with a batch of green coffee beans that are soaked in water to remove the caffeine and many of the flavor compounds as well. These beans are then discarded. This process need only happen once because the mixture produced by soaking those beans, called green coffee extract (GCE), can be maintained and reused to decaffeinate many batches of green beans. 

The idea behind WP is that water can only absorb a set amount of flavor compounds and caffeine before it is completely saturated. That first batch of beans created a fully saturated water mixture, also known as the GCE. In order to process the beans for decaffeination, the GCE is run through a filter to remove the caffeine. Now the GCE is fully saturated except for caffeine, so when a new batch of green beans are placed in the GCE, the only compound from the new beans that will be accepted into the GCE is caffeine, everything else will remain in the beans because the GCE is already saturated with those chemicals. 

Because WP does not use any chemicals in the process, organic beans can maintain their organic certifications. 

Carbon Dioxide (CO2)  

The CO2 method is, like water process, a non-solvent method. The difference between solvent and non-solvent methods is that solvent methods use artificially-derived chemicals while non-solvent methods use naturally-occurring ones. While solvent methods are considered perfectly safe for human consumption some roasters and customers may still prefer non-solvent methods. 

CO2 decaffeination occurs in a steel vessel. Beans that have been soaked in water are sealed in the vessel. Then, super-critical carbon dioxide–under 1,000 pounds of pressure and at about 93 degrees Celsius–is circulated through the beans. The extracted caffeine is then removed from the CO2 by removing the pressure and allowed the CO2 to turn to gas, leaving the caffeine behind and the CO2 is circulated through the beans again. 

Decisions in Decaf 

Whether you choose the ethyl acetate, methylene chloride, water process or CO2 processes, decaffeinated coffee will continue to grow in popularity due to an increased interest among Millennials and younger generations. As it does, we will be ready to address your needs with a variety of processes and beans.