The last time I wrote on decaffeinated coffees I said drinking them was like listening to good music through cheap speakers.
The analogy still stands. No matter what the decaffeination method or how careful the decaffeination procedure, coffee loses something more than the (tasteless) caffeine during the rather brutal process of removing it.
Or the coffee changes in unexpected ways. The San Alto Kenya in this month's cupping is about as peculiar (though rather pleasantly peculiar) a tasting Kenya as I have ever cupped. The Guatemala from PT's Coffee is almost as odd.
Sometimes what is lost in decaffeination is well lost, however. If flavor nuances sometimes disappear, so do flavor taints. Perhaps the scores for this month's cupping are so tightly clustered in the mid-80s because both positive qualities and negative were muted in the decaffeination procedure.
The Roasting Challenge
Of course, the absence of dramatically mediocre or defective coffees in this month's cupping also could be owing to the skill of the coffee buyers and the tact of the roastmasters. Particularly give the roastmasters credit: Decaffeinated coffees are notoriously difficult to roast. They arrive at the roasting plant already brown in color, and tend to roast very quickly or unpredictably. Although a couple of the coffees I cupped for this month's article betrayed a slight rubbery taste when cold, by and large this was a very well-roasted set of decaffeinated coffees.
Decaffeination Methods and Controversies
To briefly review decaffeination methods and their controversies: Most specialty coffees sold in North American are decaffeinated by one of two methods. The "European" method involves 1) steaming the beans to open their pores, 2) exposing them to a solvent (usually methylene chloride, sometimes the fruit derivative ethyl acetate) which selectively unites with the caffeine, and 3) steaming the beans again to remove both solvent and caffeine.The "Swiss Water Process" (carried out in Vancouver, Canada, not Switzerland) involves 1) soaking almost everything out of the beans except the wood, 2) running the flavor-charged water through activated charcoal filters to remove the caffeine, and 3) returning the beans to the water, where they reabsorb the now caffeine-free flavor components.
Occasionally coffees appear on the specialty market that have been decaffeinated through the use of partially liquefied CO2, which, like solvent, selectively unites with the caffeine.
The European method, with its multisyllabic solvents, sounds scary, but it is probably perfectly safe. It is highly unlikely that any solvent residue whatsoever makes it through the intense, prolonged heat of roasting. Methylene chloride is extremely volatile, and during roasting coffee is held at temperatures exceeding 400 F, often for as long as 20 or 25 minutes. Nevertheless, methylene chloride is accused of contributing to ozone destruction, and many of us prefer to avoid encouraging the use of solvents in any context, two good reasons to prefer non-solvent processes like Swiss Water. Ethyl acetate, the other solvent commonly used in decaffeination, apparently does not attack the ozone layer and is derived from fruit, which facts encourage some retailers to call coffee decaffeinated through its use "naturally" decaffeinated.
Decaffeination Methods and Flavor
What about decaffeination method and flavor? To my knowledge the most telling experiment has never been performed: a panel of professionals cupping the same coffees from the same farms decaffeinated at the same time by competing methods. But, for what it's worth, I have found that the Swiss Water Process tends to emphasize body, de-emphasize acidity and high notes, and occasionally (but not always) alter or blur flavor, whereas the European or solvent method tends to preserve acidity, nuance, and high notes, but may reduce body and dimension.
The results of this cupping strongly support those generalizations. The odd transformation by the Swiss Water Process of two notably distinctive, acidy coffees, the Kenya and Guatemala, into something full, round and rather low-toned in character, are cases in point. Both were decaffeinated by the Swiss Water method. Further support for the hypothesis: Coffees in the cupping that preserved brightness but displayed light body and little at the bottom of the profile invariably were decaffeinated by the European or solvent method.
Read the Fine Print and Enjoy
Even though none of the coffees in this month's cupping attracted a rating over 90, there were several very attractive and distinctive coffees in the mix. If readers take the time to read the fine print, they should be able to find a decaffeinated coffee that perfectly suits their taste among these twelve candidates, whether it is a big, classic, acidy coffee like the San Alto House Blend, a bright, delicately acidy coffee like the Mountain Country House Blend, a sweet, low-acid, delicate cup like the Appassionato Decaf, a deep, idiosyncratic cup like the San Alto Kenya or the PT's Coffee Guatemala, a musty Sumatra cup (San Alto) or a sweet, aromatic Sumatra (Caffe Appassionato), or the dark-roasted Humboldt Bay Good, Strong Blend that preserved a touch of fruit and spice in its rough, roasty tang.