The answer will vary depending on the beans and brewing method, but a typical 1-ounce shot of espresso contains between 40-63 mg of caffeine. According to Kicking Horse Coffee, a typical 1-ounce shot of espresso contains 40 mg of caffeine (compared to 12-16 mg of caffeine per ounce of coffee.) However, Consumer Reports cites Department of Agriculture data that shows the average shot of espresso has up to 63 mg of caffeine.