how many mg of caffeine in starbucks doubleshot espresso can?
Jun 23, 2016 · The Starbucks DoubleShot Espresso contains 125 mg caffeine per 6.5 fl. oz or 192 ml can, this equates to 19.23 mgs of caffeine per fluid ounce (65.03mg/100 ml). One shot of espresso is generally about 30–50 ml (1–1.75 oz), and contains about 63 mg of caffeine (3).