Less than hot coffee, size for size
Cold brew has a reputation as the strong option. By Starbucks’ own figures it isn’t, at least not against Starbucks’ hot brewed coffee. A Grande Cold Brew carries 205 mg; a Grande Pike Place Roast carries 315 to 390 mg. Starbucks makes its cold brew by steeping grounds in cool water for 20 hours, and serves it over ice.
Where cold brew does climb is size. The iced cups go up to 24 oz (Venti, 310 mg) and 30 oz (Trenta, 360 mg), bigger than any hot cup. A Trenta is four and a half standard cans of Red Bull (80 mg each), and 40 mg short of the 400 mg daily figure the FDA cites for healthy adults.
Nitro and the cream-topped versions
Nitro Cold Brew is Starbucks’ cold brew infused with nitrogen. A Grande Nitro carries 280 mg, 75 mg more than a Grande Cold Brew, and it comes only in Tall and Grande.
The sweet cream versions go the other way. Vanilla Sweet Cream Cold Brew carries 185 mg in a Grande and 315 mg in a Trenta, 10 to 45 mg less than plain Cold Brew of the same size. The seasonal Pumpkin Cream Cold Brew matches it size for size. Starbucks’ iced brewed coffee, a separate drink, is close: 185 mg in a Grande and 320 mg in a Trenta.
Timing matters more with a big iced cup
Cold brew is often an afternoon order, and iced drinks tend to be sipped over a longer stretch. With caffeine’s mean half-life of about five hours (NCBI), roughly half of a 3 pm Grande, about 100 mg, is still circulating at 8 pm, and a quarter at 1 am. If sleep is the problem, the size and the time of the last cup matter more than the brewing method.
The single-dose view is worth knowing too. EFSA assessed single doses up to 200 mg as not raising safety concerns for healthy adults; a Tall is under that, a Grande is just over it.