Do you know how much caffeine is in your cup of coffee? Caffeine content is such a tricky thing - the right amount can give you the jolt you need to throw your cape on and conquer anything, but too much of it and you can expect to live an anxious, jittery existence for a bit!
While an 8-oz cup of coffee contains between 80 and 100 mg of caffeine (U.S. Food and Drug Administration), there are quite a few factors that determine the exact caffeine content in your cup of joe. We'll explore what you need to know about coffee and caffeine below.
Type of coffee beans
We cultivate two main types of coffee beans for consumption in our part of the world: Coffea arabica aka arabica coffee beans, and Coffea canephora aka robusta coffee beans.
Arabica beans are grown dominantly in Latin America and feature a sweeter, softer, more floral tasting flavor than Robusta beans. In addition, Arabica beans tend to produce coffees that are more acidic than Robusta beans.
Robusta beans are primarily grown in the Eastern hemisphere (think Africa and Indonesia), feature a stronger, nuttier taste than Arabica beans, and contain twice as much caffeine content.
If you want to keep up with the caffeine content in your coffee, knowing the type of bean you're consuming is a great place to start.
Type of Roast
Pop Quiz: Which roast do you think contains the most caffeine? Light, Medium or Dark?
If you answered "Dark Roast" you're not alone in your thinking. There is a common misconception that the darker the bean, the more caffeine, but Light Roast coffees take the cake when it comes to caffeine content. Since lightly roasted beans cook for a shorter time and at a lower temperature (beans are heated to 350 F – 400 F), they hold on to more of the caffeine from the original green (coffee) bean.
Medium coffee beans stay in the roaster a little longer and are heated to 410 F – 430 F. Due to the higher temps and longer cooking time, the coffee beans lose potency. Medium roasts are less acidic than lighter roasts and don't have as much as caffeine.
Coffee beans' natural flavors and caffeine content succumb to the 465 degree temperatures needed to make Dark Roast coffee. The result is a roast that is light on the caffeine, but heavy on bold, smokier flavors.
Brew Method
If you've seen our Brew Guide, then you already know that the brewing method you choose determines coffee grind size and steeping time. The same factors apply to caffeine content - steeping time and coffee grind size causes caffeine levels to fluctuate. How about we break it down by brew method?
Brewed Coffee
The average caffeine content in coffee mentioned earlier (80-100 mg) is based on 8-oz cup of brewed coffee. By brewed we mean coffee that is made by allowing hot water to pass through coffee grounds and a filter, so this includes Drip coffee, Pour Over coffee, French Press coffee, and Aeropress coffee.
Cold Brew
Cold brew is made without heat by immersing coarsely ground beans in cold or room temperature water between 12 and 24 hours. Cold brew contains more caffeine than hot brewed coffee due to the longer steeping process. A 12-oz cup of cold brew can get you between 153 mg and 238 mg of caffeine.
Espresso
Finely ground coffee beans and whole lot of pressure is what you need to brew espresso coffee. This method produces a strong, thick brew with a consistency like warm honey. A single 1-oz shot of espresso contains about 63 mg of caffeine.
Serving Size
We can all agree that "a cup of coffee" comes in several sizes, right? An 8-oz cup is just the beginning! When trying to determine caffeine content in your coffee, whether your cuppa is 8-oz, 20-oz, or somewhere in between will cause the amount to vary significantly.
How long does caffeine last?
When caffeine enters your body, it increases energy levels and enhances your mood by raising your heart rate and blood pressure. It takes about 15-45 mins for caffeine levels to peak in your blood and it's during this time period that most of us experience those superhero effects we mentioned earlier. Caffeine has a half-life of about 5 hours, so if you consume 100 mg of caffeine, 5 hours later, you'll have 50 mg remaining in your system.
The amount of time you feel the effects of caffeine depends on your chemical makeup - your caffeine tolerance and general sensitivity. Some people report feeling the effects for several hours or days after consuming coffee.
For more details on brew methods to make the perfect cup of coffee check out our Brew Guide.