There has been confusion as to what type of coffee has the most caffeine. Conventional wisdom would presume that bold, dark roasted coffees have the most caffeine. That is not the case. It depends on the weight of the coffee and how much is used to brew a cup or pot. So, how can you know which roast gives you more caffeine? Let’s get to the bottom of this.
As you roast coffee beans, they lose water and become more “puffy”. The longer you roast, the more this happens to the bean. Darker roasted beans weigh less when measured by volume. So you are getting more caffeine in lighter roasted beans if you have the same volume of both roast types. Put another way, one cup of light roasted beans are denser and heavier and contain more caffeine. So, make a pot of light roast and get a bigger caffeine buzz. Make sense?
Now, Let’s talk about the 2 main types of coffee plants used worldwide. There is Arabica and Robusta. It is agreed that Arabica beans make for a higher quality coffee than Robusta. However, Robusta beans contain approximately TWICE as much caffeine (68-81g/kg) as Arabica beans (34-38g/kg).
Let’s consider the way the coffee is brewed/made and how much caffeine you consume.
Regular brewed coffee
A typical 8 oz cup of brewed coffee contains around 100 mg of caffeine.
The decaffeination process leaves about 2 mg of caffeine left in your cup.
Due to the light powders and granules of instant coffee (remember the volume/weight rule) there is around 62 mg in an 8 oz cup of instant coffee
Because cold brew coffee involves letting the grounds sit is water for 8 to 24 hours, there is more caffeine in a typical cup. It can vary from 150 mg to 250 mg of caffeine per 8 oz cup.
Espresso coffee is made by forcing very hot water through finely grounded coffee beans. This gives it a higher caffeine content than a regularly brewed cup. However, the smaller serving makes for less caffeine, averaging around 60-65 mg/cup.
As a rule of thumb, it is recommended that adults consume no more that 400 mg of caffeine each day, to avoid any side effects. So, taking into account the information above, drink accordingly.