What IS decaf anyway?

by Barbara Gerard, for The Coffee Project

It's close to the end of a dinner party you've hosted for your closest friends. Yes, this means it's time for the piece de resistance -- fresh roasted coffee! You're pouring the bright green beans into the roaster when one guest queries "Do you have any decaf?"

Why yes, as a matter of fact, you do. When you pull out your supply of green decaf beans the physical differences between regular and decaffeinated beans is striking. Compared to the unprocessed beans, which are plump and green, the decaf appear stunted: and shriveled, with a brownish tint, almost as if they were already roasted. What path have these beans traveled to lose that component called caffeine, and take on this striking difference?

Most caffeine-free coffee that we find here in the States has made a side trip from its growing region to a decaffeinating plant in Switzerland, Germany, or Holland. Here the beans are processed by one of two basic methods (although there are many patents for removing caffeine from coffee beans, those that are currently used fall into one of two categories).

One method is called Direct Contact. Here the green beans are soaked in very hot water for several hours. After draining, the water is transferred to another tank where it is combined with a chemical solvent (usually methylene chloride) that absorbs much of the caffeine. The solvent is much lighter than the water, so the caffeine-laden solvent is easily skimmed off. Since the water still contains the important oils it is then returned to the first tank, where the green beans reabsorb the water and oils.

Some individuals are concerned about the possible consumption of residual chemicals while enjoying their cup o' decaf. Although methylene chloride has not been implicated in any known disease, the FDA has limited the quantity of the solvent to ten parts per million in ground coffee. Your supplier of green decaf should be able to tell you the average remaining in theirs. In an attempt to assuage fears, it is pointed out that the FDA limit relates to green coffee beans, and methylene chloride is quite volatile when exposed to heat -- it vaporizes at 104øF. After the beans are roasted (400øF) and brewed (200øF), there's only a trace of methylene chloride left...if any.

The other popular method is commonly referred to as the Swiss Water Process. In 1979 a Swiss firm named Coffex S.A. introduced its process which uses water only -- no chemical solvents. In this relatively expensive process the beans are soaked in very hot water. As with the Direct Contact Method, the water leaches out the caffeine along with oils and other flavor components. Rather than using a solvent which the alkaloid (caffeine) adheres to, the Swiss Water Process uses a charcoal filtration system that removes only the caffeine. The beans are then returned to the water, where they are reconstituted.

So which method is better? The answer falls within the realm of personal choice. Many people feel the Direct Contact Method maintains the oils and other materials important to a coffee's flavor much better than the Swiss Water Process. Others think the Swiss Water Process produces a fine cup, with no risk of ingesting a chemical that we may discover causes health problems somewhere down the road.

My only suggestion is that decaf beans not be the ones you parade around the table as you seek new converts to home roasting.

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