Almost all brands of decaffeinated coffee still contain some caffeine. In an independent research on decaffeinated coffees, researchers found that all but one contained caffeine.

Drinking five to ten cups of decaffeinated coffee could deliver as much caffeine as would one or two cups of regular coffee do, after a study at the University of Florida.

There are several methods for decaffeinating coffee, but most involve soaking the green coffee beans for a period of several hours. This process removes about 97% of the caffeine, but also most of the flavor molecules. A small amount of caffeine is left in decaffeinated coffee (around 3%).

The need to remove caffeine could become unneeded if coffee growers begin using a naturally caffeine-free bean produced in June 2004. 

There are several methods of producing decaf coffee, the Roselius process, the Swiss water process, the Direct method Indirect method, the CO2/O2 process and the Triglyceride process.

The Swiss Water process activates carbon then filters the caffeine from the bath, and the beans soak to re-absorb the flavor. Alternatively, an initial batch of beans may be used to saturate the bath with flavor molecules so that consequent batches do not lose these molecules in the process. This method does not use chemicals to decaffeinate. 

In the indirect method, hot water circulates through the beans which removes the caffeine and flavor molecules. The bath is rid of the beans and the water is treated with methlylene chloride which binds to the caffeine. The CO2/O2 process and Triglyceride process are also inderct methods.

The direct method is used in products that claim, "Naturally decaffeinated coffee." This process uses ethyl acetate, a natural molecule found in some fruits that easily binds with caffeine. The method is similar as above except that the beans are not removed from the bath and come in direct contact with ethyl acetate.