Ristretto shots in a smaller milk ratio
A Starbucks Flat White is made with ristretto shots and steamed milk. Ristretto is a shorter espresso extraction, so the shot is more concentrated in flavour but not necessarily higher in caffeine. The higher caffeine in a Flat White comes from using more espresso shots relative to milk than a standard latte of the same size.
Starbucks lists 130 mg in a Short or Tall and 195 mg in a Grande or Venti. A Grande Flat White therefore has 45 mg more caffeine than a Grande Caffè Latte at 150 mg. That difference is meaningful: the Flat White comes within 5 mg of the 200 mg EFSA assessed as a safe single dose for healthy adults, and to roughly half of the FDA’s 400 mg daily reference for healthy adults.
Milk texture, not milk volume
The drink is known for its velvety microfoam, created by steaming milk to a fine, glossy texture. The milk volume is similar to a latte, but the foam is denser and the espresso-forward balance is stronger. If you prefer a coffee-forward drink with more caffeine than a latte but less than a straight americano, the Flat White sits in that middle range.
The milk matters for texture, not caffeine
Starbucks uses whole milk by default for the Flat White. Switching to skim, oat, almond or another milk alternative changes the fat and sugar profile but does not change the caffeine number, because the shots stay the same. The 195 mg in a Grande comes from the espresso, and the microfoam is simply the steamed milk that carries it. The same rule applies to the Iced Flat White: the espresso count is unchanged.
Source
The caffeine figures are from the Starbucks published nutrition page for Flat White, checked 19 September 2026.