The Coffee Revolution : The Decaf Dilemma
Some people don’t want caffeine in their coffee because it makes them jumpy. Some people don’t want caffeine because their doctors tell them they shouldn’t have it. And some people are Brazilian--no one knows what’s different about their metabolisms, but an amazing number like “a soothing cup of coffee” at bedtime.
The idea of decaffeination--removing 96% to 98% of the caffeine from coffee beans before roasting--began in Europe but has caught on mostly over here. The Tea and Coffee Trade Journal reports that about one cup out of four in this country is decaffeinated, or about 0.4 cups of decaf per person per day. Americans may consume 60% of all the decaf in the world.
The trouble is that taking out the caffeine inevitably means taking out some of the flavoring elements in the coffee. You apparently have to accept a trade-off between caffeine and flavor.
One of the oldest decaffeination methods, and the one that most coffee connoisseurs think harms the flavor of coffee least, is the direct methylene chloride method. The beans are simply soaked in methylene chloride, a solvent that removes the caffeine and very little else.
Many people don’t like the methylene chloride process because trace amounts of this carcinogenic chemical persist in the bean. However, their fears may be exaggerated. Methylene chloride evaporates well below the temperature of boiling water--to say nothing of the temperature at which coffee beans are roasted (390 to 440 degrees)--and so little survives the brewing process that no study has ever been able to detect it in the cup. Since, on the other hand, it takes massive doses of methylene chloride to give lab rats cancer, in 1989 the FDA determined that the risk of cancer for a heavy lifetime drinker of decaffeinated coffee was one in a million.
Others fear that methylene chloride may be degrading the ozone layer by adding chlorine ions to the atmosphere. This hasn’t been substantiated, and since natural sources of atmospheric chlorine greatly dwarf all human contributions, it may never be. If methylene chloride turns out to be a danger, people will also have to worry about painting their homes--methylene chloride is better known as paint thinner.
For those who want to avoid methylene chloride decaf, other methods have been devised. One is the indirect methylene chloride method, also called the European water process. Here coffee beans are soaked in water, which extracts a lot of their contents; then methylene chloride is added to the water, which removes the caffeine but leaves the flavoring elements. The process is repeated over and over with fresh beans, and theoretically the concentration of flavoring elements eventually becomes so high that the water can’t absorb any more of them and from then on only extracts caffeine from beans.
The European water process is not to be confused with the Swiss Water Process, a method patented by the Coffex Co. The Swiss method uses the same technique of soaking in water saturated with flavoring elements, but instead of being removed from the water with methylene chloride, the caffeine is filtered out by the use of specially activated charcoal. The process has been improved over the years (for instance, these days they’re careful to make the soaking water from the same kind of beans that are being decaffeinated), but many coffee connoisseurs still feel that much of the flavor is lost.
“Natural process” decaffeination uses other solvents, such as ethyl acetate or liquid carbon dioxide. Hills Bros. uses a patented method based on “coffee oil"--the name for oils in the coffee bean that are soluble in petroleum ether. Some beans are sacrificed to produce this oil (or rather, a lot of beans--Hills ships its coffee oil in tanker trucks). Then beans are exposed to water and coffee oil under pressure and steam, and the oil dissolves the caffeine.
Tim Castle, president of the Specialty Coffee Assn. of America, predicts that decaffeination will convert to other solvents, principally ethyl acetate, in the next three to five years because of European Economic Community regulations whose effects will spill over into the American market.