|MadSci Network: Medicine|
I have included a brief description of the process by which decaffeinated coffee is made. When purchasing decaffeinated coffees, it is helpful to understand the processes used. Opinions differ as to which process is "better". Both remove at least 97% of the naturally-occurring caffeine from the beans.
The green coffee beans are steeped in hot water, which gradually removes the caffeine. The water is separated from the beans and treated with methylene chloride. In this process, the solvent never touches the actual bean. The solvent absorbs the caffeine, which is removed with heat by a process of evaporation. The vital coffee oils in the remaining water are then added back to the beans. Many customers prefer this method because the flavor of the coffee is least affected by this process.
SWISS WATER PROCESS
Here the beans are immersed in water, without chemical additives, for several hours until the caffeine is removed. The resulting solution, which contains caffeine as well as the other essential coffee elements, is passed through activated charcoal or carbon filters to remove the caffeine. Then the coffee elements are added back to the beans.
Amount of caffeine per serving in milligrams
Espresso 100mg of caffeine
Decaf, brewed 3-4mg
Decaf, instant 2-3mg
Tea, iced (12 ozs.) 70mg
Thus from the above please note that even decaffeinated coffee does contain caffeine, albeit, in much smaller amounts than non-decaf. As far as raising blood pressure I cite from a paper by Green and Shuls (1),who measured heart rate and blood pressure in coffee drinkers drinking decaf with either added caffeine or cornstarch. In this group of people systolic and diastolic pressures were elevated on the day caffeine was consumed, not when cornstarch was added.
1. Green, Suls The effects of caffeine on ambulatory Blood Pressure, heart rate and mood in coffee drinkers. Journal of Behavioral Medicine.1996 April 19 (2) 111-28.
hope this helps,
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