There are two factors that affect the amount of caffeine in a coffee bean: how they’re roasted and how they’re prepared.
Some people believe the darker the roast, the more caffeine the coffee beans have. Actually, these people are completely mistaken. It’s he opposite. Sure, dark roasts have stronger taste, but the roasting procedure they experience decreases their caffeine content by 10 to 15 percent. If you prefer dark roasted beans, congratulations! They basically contain 15% to 20% less caffeine than the light roasted ones.
Additional fact: Although roasting only lasts for 10-15 minutes, they involve high temperatures higher than 350 degrees Fahrenheit!
The second factor is how the coffee is prepared. For instance, with the use of the Espresso method, one ounce of coffee will only consist of 30-50 mg of caffeine. Although using the drip method the coffee will have less content, dripped coffee are generally consumed more and served in bigger cups. The Journal of the American Dietetic Association reported that a normal cup of brewed coffee using the drip method contains 107-151 mg of caffeine. The exact amount varies from the roast and type of bean. If you drank 8 oz. of drip Arabica, you’ve consumed 200 mg of caffeine already.
Arabica coffee beans are widely used and generally contain 1.1 to 1.4 percent caffeine per bean. That percentage only illustrates the amount of caffeine during the coffee bean’s first extraction of water. That’s only about one to two milligrams, depending on how small or big the bean is. You have to consider that caffeine is still present even when the first extraction is over.
Fortunately, Crackheads, one coffee manufacturer, agreed to conducting a test for their chocolate covered coffee beans. The test found out that about 6 mg of caffeine per bean. The chocolate only had 1 mg of caffeine and when that was deducted from the 7 mg per bean, the answer was of course, 6 mg.
But then again, the brewing method may affects the bean, so that 6 mg of caffeine per bean only represents the amount of caffeine in Arabica chocolate covered coffee beans.
On the other hand, Robusta beans contain higher caffeine content than Arabica beans. They’re even accepted to have twice the amount of caffeine than Arabica beans. That would mean a Robusta bean could contain around 11 to 12 mg of caffeine.