decaf coffee

A controlled study of ten samples of prepared decaffeinated coffee from coffee shops showed that some caffeine remained. Fourteen to twenty cups of such decaffeinated coffee would contain as much caffeine as one cup of regular coffee. The 16-ounce (473-ml) cups of coffee samples contained caffeine in the range of 8.6 mg to 13.9 mg. In another study of popular brands of decaf coffees, the caffeine content varied from 3 mg to 32 mg. An 8-ounce (237-ml) cup of regular coffee contains 95–200 mg of caffeine, and a 12-ounce (355-milliliter) serving of Coca-Cola contains 36 mg. Both of these studies tested the caffeine content of store-brewed coffee, suggesting that the caffeine may be residual from the normal coffee served rather than poorly decaffeinated coffee.