Jun
4
Despite some confusion, on a per-volume basis, espresso contains approximately three times the caffeine content of regular brewed coffee (1.700 g/l (50 mg per fluid ounce) of espresso versus 0.50-0.75 g/l (14-22 mg per ounce) for brewed coffee). Compared on the basis of usual serving sizes, a 30 ml (1 fluid ounce) shot of espresso has about half the caffeine of a standard 180 ml (6 fluid ounce) cup of American-style coffee, which varies from 80 to 130 mg.
Espresso - Wikipedia
