Decaf coffee is coffee that has had the caffeine removed. Caffeine, a tasteless component of coffee, is responsible for the stimulant effect that is desired by many who drink coffee. Decaffeinated coffee is not only in demand by those who want to avoid the stimulant effects of caffeine, but also consumers concerned about their health and diet. The demand for decaf coffee has grown dramatically and now accounts for more than 17% of the total coffee consumption.
There are two methods employed by the coffee industry to remove caffeine from the coffee beans. The more widely used European method is a chemical process that uses Methylene Chloride. Although the chemical process sounds harsh, it is actually quite safe and tests have not been able to detect the presence of Methylene Chloride in the coffee. It’s interesting to note that close to 80% of the decaf coffee produced worldwide is processed using this chemical process.
The other process preferred by many is the Swiss Water Method. The Swiss Water Method does not expose the coffee beans to any chemicals and is the only decaf process that is certified organic.
- Direct Methylene Chloride method – the green coffee beans are placed in a rotating drum and steam is used to soften the beans for about 30 minutes. In the drum, the beans are rinsed with Methylene Chloride, a chemical solvent, for 10 hours. The Methylene Chloride removes the caffeine from the coffee beans. The beans are exposed to steam again for another 8 to 12 hours to allow any remaining solvent to evaporate.
- Indirect Methylene Chloride method – the green coffee beans are soaked in a water and coffee solution for several hours at near boiling temperatures. This soaking draws the caffeine, flavor elements and bean oils into the solution. The resulting caffeine/coffee solution is treated with Methylene Chloride to remove the caffeine. The solution is then re-heated to evaporate the methylene chloride solvent. The beans are then reintroduced to the solution and allowed to soak until they have reabsorbed most of the flavor elements and oils back from the solution. This process is called indirect because the methylene chloride never makes direct contact with the beans.
- Swiss Water Process – in the first stage, the green coffee beans are submerged in a bath of heated water, which removes both the flavor elements and the caffeine from the beans. This first startup batch of beans is discarded and the resulting solution becomes what is called the “flavor-charged” water. The caffeine is removed from the “flavor-charged” solution using special carbon filters. This solution becomes the medium for subsequent batches of green coffee beans.
When the subsequent batches of green coffee beans are soaked in this “flavor-charged” solution, the beans give up their caffeine, but not their essential flavor components and oils. The high concentration of the flavor elements and oils already in the solution (extracted from the discarded first batch of beans) prevents additional flavor components from being released into the solution from the subsequent batches of beans. The beans do release their caffeine into the solution since the concentration of caffeine in the solution is kept low by the carbon-filtering step.
The beans are then dried and packaged for distribution.
Is Decaf Coffee Safe?
Although the chemical processes used that employ solvents sound harsh, they are actually quite safe. Methylene Chloride evaporates very easily at such a low temperature, very little if any is left behind. During the roasting process, any residual methylene chloride (if any) will completely evaporate at the 400F or higher temperatures. After coffee is roasted, testing labs have been unable to detect any residual trace of chemical solvent introduced during the decaffeination process. The Federal Food and Drug administration considers both the chemical and Swiss Water methods to be safe.