|Are you one of those people — and you know who you are — who happily sips, no matter the hour, large lattes, colossal cappuccinos and mammoth mugs of brew without regret, without losing a moment’s rest, thanks to a little process called “decaffeination”? But in the course of cutting back on the source of blame for multifarious maladies like headaches and indigestion, you may have overlooked what occurs during the process of removing most of the caffeine, a naturally occurring chemical, from a coffee bean.Of course, you may not want to consider this reality, as thoughts of pesticides, bovine growth hormones and genetic alteration already plague many a conscience during a grocery store visit. Why torture yourself by adding worries about the decaf coffee bean? After all, you’re trying to do something good for your body by cutting back or eliminating that cursed caffeine. Right?
Well, not everyone believes caffeine to be the worst of coffee evils. According to Dr. Andrew Weil, who proffers medical opinions on the “Ask Dr. Weil” Web site, decaf not only contains enough caffeine to harm those who must avoid it (regular coffee is one to two percent caffeine by weight; decaffeination removes about 97 percent of it), but it also harbors other substances naturally found in coffee beans that can irritate the body. In other words, decaf can be just as tough on the stomach as regular coffee.
Continuing on the perils of decaf dependence, Dr. Weil says, “If you really want to have a cup of decaf, I’d recommend using only the water-extracted versions. There’s concern that some traces of solvents remain in coffee decaffeinated by other methods, although manufacturers deny it.”
You can thank German chemist Ludwig Roselius for the decaf solvent residue. Roselius, who reportedly believed excessive coffee drinking had poisoned his father, set about in the early 1900s to discover a way to extract caffeine from a coffee bean. Before World War I, he realized that several compounds dissolved the caffeine in beans without affecting coffee’s flavor in the cup. Chloroform and benzene both did the trick, but had Roselius’ father consumed cups decaffeinated by these chemicals, he would’ve been affected by the toxic films remaining on the bean. Subsequently, methylene chloride prevailed as the removal compound of choice.
Extraction using methylene chloride is known as the direct method, which means that green (unroasted) beans are first steamed or soaked — to bring the caffeine to the surface — and then treated with a solvent (like methylene chloride) that bonds with the caffeine. The caffeine can then be rinsed, steamed or evaporated away.
The problem with methylene chloride is that in the 1980s, it was discovered to be a suspected carcinogen — in massive amounts, it can cause tumors in lab animals. The U.S. Food and Drug Administration permits use of the solvent as long as the residue remaining on the finished product is no more than 10 parts per million. Residue on decaffeinated coffees that have been treated by this method is generally less than one part per million. The process continues to be used in part because it barely disturbs the flavor of coffee.
Other solvents can also take the kick out of your cup. Ethyl acetate, a chemical that occurs in fruits, is considered a “natural” solvent.
The patented Swiss Water method is another popular caffeine-extraction method, particularly among those who are anti-residue. Here, green beans are soaked in a warm-water bath. As the beans’ pores open, they sweat caffeine into the water. This caffeinated water — corporate name “flavor-charged water” — is drained from the bean bathtub via activated carbon filters that remove the caffeine yet leave the flavor compounds alone. The caffeine-free water is then reintroduced to the green beans, which resoak the flavors, and voila! decaf. The drawback to Swiss Water decaf is that some of the beans’ oils also get rinsed away in the process, which can affect the end flavor.
In yet another decaffeination process, all-natural “supercritical” carbon dioxide is used. Beans are placed in a holding tank under tremendous pressure. They’re then steamed, and when their pores open, caffeine is dissolved into water inside the bean. Carbon dioxide (a liquid at this enormous pressure) is added to the vat and agitated throughout the beans. The CO2 subsequently forces the caffeine molecules out of the beans. This caffeine-infested CO2 is then transported to a different pressurized tank for recovery of the caffeine via pressure and water. The caffeine is removed, then likely sold to soft-drink manufacturers, and the purified CO2 is recirculated to extract more caf from another bean batch.
But wait: there’s more.
Scientists at the University of Hawaii are experimenting with plants that could produce caffeine-free beans, which, rumor has it, will produce a better cup of coffee.
The process of biotechnically removing caffeine from the coffee plant involves isolating the protein that creates the caffeine gene. Once the protein is identified, scientists then isolate the caffeine gene and effectively remove it through a process called “anti-sense,” which removes the regular gene, turns it backward, and reinserts it. If the gene’s activities are squelched so the protein can’t be created, the caffeine can’t be made.
The university owns the patent for the bean, as well as the process that created it, and is leasing the technology to Honolulu-based Integrated Coffee Technologies, which hopes to grow and market the first plants.
The genetically altered decaf could reach your grocery store shelf by 2006. Luckily you’ve got six stress-free years to go.