by Minute Major

Created on: June 15, 2010

Caffeine is a psychoactive molecule naturally present in many everyday foods and beverages ranging from chocolate to tea. The stimulating effects of the drug are sought after by early morning risers and fatigued mid-day workers alike. The effects of caffeine on the human body differ in the amount consumed, as in many drugs. Therefore, regulation of caffeine intake should be monitored to eliminate negative effects of the compound.

Coffee is one of the most popular beverages consumed today; in fact, over 400,000 cups of coffee is consumed each day by Americans alone. The caffeine content of coffee depends on various conditions such as coffee species, brewing process, and roasting.

Coffee Types

There are two types of coffee commonly grown world-wide: Robusta and Arabica. The coffee produced by the beans of these two plants differs greatly in taste and caffeine content. Robusta beans are generally lower quality beans, cheaper priced and create a more bitter taste than its Arabica brother. However, Robusta beans contain 1.7 – 4.0 % caffeine content, up to 3 times as much as Arabica beans. Most Robusta beans are sold in a tin or plastic container, often pre-ground.

Arabica on the other hand is considered a high-quality coffee that features rich flavors and offers delectable tasting notes with a smoother aftertaste. The caffeine content of Arabica beans is between 0.8 and 1.4%.

Brewing

The strength of coffee primarily affects the amount of caffeine in a cup of Joe. A stronger coffee will contain more caffeine, while a weaker cup contains less. The strength of coffee is often determined by 3 factors: amount of ground coffee used, grind type, and brew time. Coffee beans can be ground finely or more course. In general, the finer the grind, the more surface area for brewing and the stronger the coffee. A courser grind is, however, often preferred as it favors a less bitter cup of coffee. Different brewing techniques are often implemented to create different coffee qualities. For instance, espresso is a concentrated coffee beverage made by forcing hot water through finely ground beans at high pressure, brewing a thick coffee with a higher caffeine ratio. Due to being served in a smaller serving size, one shot of espresso contains less caffeine than the standard cup of coffee.

Roasting

Coffee beans start out green and must be roasted to acquire certain flavors before being brewed into a beverage. The amount of time spent roasting determines whether the coffee is darkly roasted or on the lighter side. Contrary to popular belief, a darker roasted coffee has lower caffeine content than a lighter roasted coffee.

So, considering these factors, how much caffeine is in a cup of coffee? This table should give a good understanding of the caffeine content in a 6 oz. cup of coffee.

Espresso (180 – 300 mg)

Robusta Coffee Drip (140 - 200 mg)

Arabica Coffee Drip (75 – 130 mg)

Instant Coffee (40 – 100 mg)

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