[Responsibility2nd]

Found on the web

Espresso has 63 mg of caffeine in 1 ounce (the amount in one shot), according to Department of Agriculture nutrition data. Regular coffee, by contrast, has 12 to 16 mg of caffeine in every ounce, on average. That means that ounce for ounce, espresso has more caffeine.

Jun 13, 2021

[Dr. Sivana]

Espresso has 63 mg of caffeine in 1 ounce (the amount in one shot), according to Department of Agriculture nutrition data. Regular coffee, by contrast, has 12 to 16 mg of caffeine in every ounce, on average. That means that ounce for ounce, espresso has more caffeine.

I knew Espresso was stronger (1 oz. ≈ 6 - 8 oz. coffee, depending on the coffee). I used the alcohol analogy because a 1 1/2 oz. shot ≈ 5 oz. wine ≈ 12 oz. beer.