How Is Organic Coffee Decaffeinated?

There are four ways to decaffeinate coffee. Only one of them is certified organic. Here are the details.

Decaffeination Using Solvents

There are two methods for removing caffeine that use solvents. The direct solvent method soaks coffee beans in the solvent and the indirect solvent method beans are soaked in water and the caffeine rich water is treated with a solvent. The two commonly used solvents are methylene chloride and ethyl acetate. Both of these are very volatile chemicals so that whatever minute quantities persist in the final decaffeinated bean they are removed with roasting and then brewing.

Indirect Solvent Method

Coffee beans are soaked in hot water (just under the boiling point) for several hours. This removes caffeine as well as other chemicals that give coffee its flavor and aroma.

Water is drawn off to another container and the solvent is added. The solvent binds to the caffeine. Then the mixture is heated and the volatile solvent and caffeine evaporate. Then the beans are added to the remaining mixture to reabsorb the remaining chemicals restoring part of the flavor of the coffee.

Direct Solvent Method

In this case the beans are briefly steamed, about half an hour. Then they are rinsed with the solvent repeatedly for about 10 hours. The solvent is drained off and the beans are steamed one more time to remove remaining solvent.

Non-Solvent Methods

Swiss Water Method

Although this way to decaffeinate coffee was discovered in the 1930’s it took another half century to find a way to make the process cost effective. Despite the Swiss name the company is based in Vancouver, B.C. This is the process whose facility has organic certification.

Coffee beans are soaked in hot water to remove caffeine. The water passes through an large-pore activated charcoal filter. The pore size is such that larger caffeine molecules are trapped and smaller molecules (oils, antioxidants) pass through. The remaining water contains flavor elements but not caffeine.

Then the first batch of beans is discarded! New beans are then soaked with the flavor rich but caffeine free water. Osmosis takes caffeine out of the beans to until its concentration is the same in the bean and in the water. But the flavor elements are already equally concentrated in bean and water so they are not removed. The company tests their product to guarantee that their coffee is 99.95% caffeine free. Decaf coffee made with this process is always labeled as Swiss Water decaf.

CO2 Method

This high tech approach to making decaf coffee is relatively new. Coffee beans are placed in a very strong stainless steel tank. Then liquid CO2 (carbon dioxide) is introduced until the pressure in the tank is 1,000 pounds per square inch. Air pressure on the earth’s surface at sea level is 14 pounds per square inch so the coffee is subjected to a lot of pressure. The carbon dioxide selectively dissolves caffeine and leaves the other constituents behind. The CO2 is drawn off and allowed to return to a gas form releasing the caffeine which allows the re-liquefied CO2 to be used again and again.

This is an expensive process that is most economical on a very large scale. Thus it gets used for processing of huge quantities of ordinary decaf coffee for grocery stores.


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