There is a great deal of common misconceptions out there when it comes to understanding the delicious and complex beverage we have all come to love, espresso. Some believe that espresso is its own type of bean, type of blend, or type of roast. Spoiler alert: these are all myths.
Espresso is usually made with a blend of several different types of coffee beans from different origins but can also be created with single origin beans. The main differences between espresso and drip coffee are the fineness of the grind and the brewing time. Espresso is the product of a specific method of extraction that is impossible without the proper equipment. The brewing time for espresso coffee is substantially shorter than brewing time for drip coffee, and is made possible by espresso machines that generate up to 15 atmospheres of pressure to force the water through the coffee. Espresso beans are also ground very finely -- much finer than for drip coffee.
Drip coffee is brewed by dripping boiling water over coarsely ground coffee. This process is much slower than the espresso process, and hot water is in contact with the ground coffee for much longer. The most surprising fact of all is that a cup of drip coffee actually has more caffeine than a shot of espresso! Eight fluid ounces of brewed coffee has 65-200 mg of caffeine, and a single fluid ounce shot of espresso has 30-50 mg of caffeine. Although, It is true that if you drink an eight ounce cup of espresso (not advised!!), you will get much more caffeine than if you were to drink an eight ounce cup of brewed coffee. Overall, it is normal for espresso to have less caffeine than drip coffee because espresso is not intended to be consumed by the cup, but rather by a shot of one to two ounces.