The u003ca href=u0022https://www.healthline.com/nutrition/what-is-caffeineu0022u003ecaffeineu003c/au003e content of coffee depends on the type of bean, how it is roasted, and how it is prepared. The big question we always get is which has more caffeine, espresso or coffee. An ounce of espresso contains 63 mg of caffeine whereas regular coffee contains between 12 to 16 mg of caffeine per ounce. The amount of caffeine you take in depends on the volume of coffee in your cup.