Starbucks customers may be surprised to learn that shots, not size determine the amount of espresso in a venti drink. While ...

An iced latte has 75 milligrams of caffeine in a tall, 150 in a grande, and 225 in a venti. In comparison, the shaken espresso has 150 milligrams in a tall, 225 in a grande, and 300 in venti.

Starbucks offers three standard sizes -- tall (12 ounces), grande (16 ounces), and venti (20 to 24 ounces) -- for its handcrafted espresso-based drinks. If you're new to the Starbucks game ...