All Decafs Are Not Created Equal - How IS Coffee Decaffeinated?
The Question - How is Coffee Decaffeinated?
About 4 years ago, we made the decision to switch to decaffeinated coffee after my husband had a scary bout of atrial flutter. Several months later, he announced that he was giving up decaf, too -- it upset his stomach to the point of making him queasy.
This didn't make sense to me...how could he drink regular coffee of any brand just fine, but have a problem once the caffeine was removed? I figured that maybe something in the decaffeination process was the culprit and set about doing some detective work.
A little research revealed that there are several ways to decaffeinate coffee. The major extraction methods are:
- Chemical solvent
- Water process
- Supercritical CO2
Chemical Solvent Extraction
Chemical solvents can be used to extract caffeine in two ways, the direct method and the indirect method.
As the name implies, the direct method involves direct contact of the solvent, usually methylene chloride, with the coffee beans. First the green coffee beans are steamed for about 30 minutes to soften the beans. After steaming, the beans are soaked in the chemical solvent for about 12 hours to remove the caffeine, but leaving the flavor-producing coffee solids intact. After soaking, the beans are steamed again to remove traces of the solvent. You may see this method referred to as the "European process".
In the indirect method, coffee beans are soaked in hot water, which draws out the caffeine as well as many soluble coffee components that give coffee its flavor. The soaking solution is then exposed to the chemical solvent, either methylene chloride or ethyl acetate, which removes the caffeine. (Since the beans themselves are not exposed to the solvent, this is called "indirect".) The solution is then heated, when removes the solvent and caffeine, and the original beans are once again soaked in the solution to reabsorb the flavorful coffee solids that were stripped out.
You may see the indirect method referred to as "water process", but it should not be confused with the next extraction method I discuss, Swiss Water Process, which does not use chemical solvents at any stage. Also, the indirect method using ethyl acetate is sometimes referred to as "natural process", since ethyl acetate is a compound found in many fruits. However, the chemical used in the decaffeination process is often synthetically produced.
Swiss Water Process
Swiss Water Process is a 100% chemical free extraction method developed by the Swiss Water Decaffeinated Coffee Company. There is only one major Swiss Water Process decaffeination facility, which is located near Vancouver, British Columbia.
The key to caffeine extraction by this method is a solution called GCE, Green Coffee Extract, which is an internally developed and maintained solution. GCE is initially created by soaking a batch of green coffee beans in water until the caffeine, as well as soluble coffee components, migrate out of the beans and into the water. The original batch of beans is discarded and the solution passed through a carbon filter especially designed to remove only the caffeine molecules and leave the water saturated with soluble coffee solids.
Fresh beans which need to be decaffeinated are placed into the GCE. Because of the saturation of soluble coffee solids in the GCE, only the caffeine diffuses out of the beans, leaving the flavor-rich coffee solids. The GCE is passed again and again through carbon filters to remove the caffeine which has been extracted. The process is repeated until the beans are 99.9% caffeine-free, which takes about 8-10 hours.
After the caffeine extraction process, the beans are removed from the GCE solution, dried, bagged, tagged and ready to be roasted.
Supercritical Carbon Dioxide Extraction
Supercritical CO2 may sound a little ominous, but it simply refers to carbon dioxide which has been subjected to sufficient high heat and temperature to have the properties of both a gas and a liquid. Once coffee beans have been softened through steaming, they are bathed with a supercritical CO2 solvent. The solvent strips out and carries away the caffeine, generally leaving the flavor solids intact. The caffeine is removed from the CO2 by water or carbon filter; then the CO2 can be used again to process another batch of beans.
The advantage to this method is that is does not use any potentially harmful solvents in the decaffeination process.
The triglyceride process is a newer method of decaffeination. The coffee beans are first soaked in a water and coffee solution to bring the caffeine to the surface of the beans. Next, the beans are immersed in natural coffee oils obtained from previously used coffee grounds. After several hours at high temperatures, the triglycerides in the oils remove the caffeine from the beans, leaving the flavor components intact. The caffeine is removed from the oils, which are used to process another batch of beans.
An advantage of this process is that, like Swiss Water Process and Supercritical CO2, no toxic chemicals are used.
Our Choice - Swiss Water Process Decaf
After reviewing the information I had gathered, we decided to give Swiss Water Process decaf a try. There were several reasons for choosing this decaffeination method over the others.
First, I felt that my husband was sensitive to something used in the decaffeination process, and that it might be trace amounts of the solvents used in the chemical solvent method.
Second, whenever I choose food or a beverage, I like to stick to the whole food concept - choose a food that is as close to its natural state as possible. Anything that is exposed to chemicals and/or high temperatures or unnatural conditions is less desirable to me than something that is naturally processed.
And last, Swiss Water Process decaf is very easy to spot in the store - it has a distinctive round logo with an "S" in the middle and a wavy line under the "S". This may be present anywhere on the packaging, so if you don't see it on the front, be sure to look on the sides and back for the logo.
I've found that many decafs are not labeled as to how they are processed, so it becomes very difficult to know exactly what you're getting if it's not Swiss Water Process.
Even if you can't find Swiss Water Process locally, it's widely available online in ground, whole bean, and pod forms. So if you'd like a good cup of decaf which is good for you, brew up a pot of Swiss Water Process decaf and enjoy!