Depending on the type and origin of coffee used during the brewing, a single shot of espresso can contain between 29 and 100 milligrams of caffeine depending on the serving size. An espresso is a concentrated coffee beverage created by applying heat and water pressure to ground coffee beans.
A double shot of espresso, also known as a doppio, typically has around 150 milligrams of caffeine but can range anywhere between 58 and 185 milligrams. Espresso drinks made at Starbucks contain about 75 milligrams of caffeine for short and tall drinks, as of 2014. Grande or venti drinks contain around 150 milligrams of caffeine.