Coffee can be prepared in many ways -- from a shot of dark-roasted espresso in your latte to the morning pot of medium-roast you make at home. Its caffeine content is determined by a number of things, including the type of bean used as well as how long the beans are roasted. Boiling or cooking prepared coffee does not appear to reduce its caffeine levels.
Coffee
To make coffee, the beans of the coffee plant are harvested, roasted, ground and infused in hot water. Best-known for its high levels of the stimulant chemical caffeine, coffee also contains small amounts of carbohydrates, fats, vitamins, minerals and amino acids. It may have mild antioxidant action, contribute to increased levels of LDL cholesterol, or “good” cholesterol, and help prevent type 2 diabetes. Studies on its effectiveness for these purposes are ongoing.
Caffeine Dangers
According to researchers at the Linus Pauling Institute, a moderate amount of caffeine -- about 3 to 4 cups of coffee a day, or 300 to 400 milligrams of caffeine -- is probably harmless or even beneficial for most people. However, consuming too much may contribute to heart disease in people with hypertension and lead to miscarriage and low fetal growth in pregnant women. Pregnant women should keep intake below 300 milligrams a day or avoid it altogether. An 8-ounce cup of coffee can contain between 95 and 200 milligrams, depending on how the coffee is roasted and prepared.
Roasting and Caffeine
Coffee beans must be roasted before they can be used to make coffee. This process degrades the beans’ caffeine content. Therefore, dark-roasted coffee beans, such as espresso beans and French roast, will probably have lower caffeine levels than light- or medium-roasted coffees. Specialty beans grown on Arabica coffee trees also contain less caffeine than most commercial brands. Caffeine is removed from decaffeinated coffee through chemical processes or water or charcoal filtering.
Boiled Coffee
There is no evidence that heating or boiling prepared caffeinated coffee reduces its caffeine content. In fact, boiled coffee -- coffee prepared by adding coffee grounds directly to water, then boiling, instead of using a drip filter -- may be more toxic than filtered drip coffee, although the reasons for this relationship are not yet fully understood. A 2006 study published in “Toxicological Reviews” linked boiled coffee consumption to unhealthy cholesterol levels. However, more well-designed studies need to be conducted before any definite conclusions can be made.
References
- Linus Pauling Institute Micronutrient Information Center; Coffee; Jane Higdon; 2005
- University of Michigan Integrative Medicine: Healing Foods Pyramid – Coffee
- “Critical Reviews in Food Science and Nutrition”; Coffee and Health: A Review of Recent Human Research; Jane Higdon et al.; 2006
- “Toxicological Reviews”; Boiled or Filtered Coffee? Effects of Coffee and Caffeine on Cholesterol, Fibrinogen and C-Reactive Protein; I. M. Rodrigues et al.; 2006
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