How much caffeine is in Starbucks Iced Brown Sugar Oatmilk Shaken Espresso?
A Grande (16 fl oz) Starbucks Iced Brown Sugar Oatmilk Shaken Espresso has 255 mg of caffeine.
That's about 3 cups of brewed coffee, and two thirds of the 400 mg a day the FDA cites for most healthy adults.
Source: starbucks.com · checked 10 Nov 2026
When did you have it?
Had at 3 pm, about 90 mg is still in you at an 11 pm bedtime. That might affect your sleep.
Your whole day, every drink, in the free CaffeineIQ check. The iPhone app is coming soon.
Sizes
| Size | Volume | Caffeine | mg per fl oz |
|---|---|---|---|
| Tall | 12 fl oz (355 ml) | 170 mg | 14 |
| Grande shown above | 16 fl oz (473 ml) | 255 mg | 16 |
| Venti | 24 fl oz (710 ml) | 340 mg | 14 |
Source: starbucks.com · checked 10 Nov 2026
Latest time to drink it
For an 11 pm bedtime, most people should finish a Grande (16 fl oz) Starbucks Iced Brown Sugar Oatmilk Shaken Espresso by about 10:45 am. The table works it out for other bedtimes and for how sensitive you are: it is the latest time to start one so that the caffeine left stays under the line all night.
| Bedtime | Very sensitive under 25 mg | Average under 50 mg | Not very sensitive under 100 mg |
|---|---|---|---|
| 9 pm | Too much for one evening | 8:45 am | 1:45 pm |
| 10 pm | Too much for one evening | 9:45 am | 2:45 pm |
| 11 pm | 5:45 am | 10:45 am | 3:45 pm |
| Midnight | 6:45 am | 11:45 am | 4:45 pm |
| 1 am | 7:45 am | 12:45 pm | 5:45 pm |
For a Grande (16 fl oz) Starbucks Iced Brown Sugar Oatmilk Shaken Espresso, average clearance (half-life 5 h), 8 hours of sleep. "Any time" means even one at bedtime stays under the line.
How long it lasts
The caffeine from a Grande (16 fl oz) Starbucks Iced Brown Sugar Oatmilk Shaken Espresso peaks in your blood about 75 minutes after you start it, at roughly 218 mg. Half of it is gone in about 5 hours for an average adult; that ranges from roughly 3 to 7 hours, and longer in pregnancy or with some medicines.
| Time after | 3 hours | 6 hours | 9 hours | 12 hours |
|---|---|---|---|---|
| Still in you | 179 mg | 118 mg | 78 mg | 51 mg |
So one had at 3 pm leaves about 90 mg at 11 pm. How long caffeine lasts explains the curve.
How it compares
Starbucks Iced Brown Sugar Oatmilk Shaken Espresso is stronger than 90% of the 90 coffee-shop drinks we track, by caffeine per serving.
Per fluid ounce (16 mg) it is stronger than 88% of them.
To reach 400 mg in a day you would need about 1½ of these.
Less caffeine
- Starbucks Cortado 230 mg, Short
- Dutch Bros Cold Brew 226 mg, Medium iced
- Starbucks Aerocano 225 mg, Grande
More caffeine
- Starbucks Vanilla Sweet Cream Nitro Cold Brew 265 mg, Grande
- Starbucks Nitro Cold Brew 280 mg, Grande
- Dunkin' Frozen Coffee 295 mg, Medium
Same caffeine: Starbucks Iced Hazelnut Oatmilk Shaken Espresso, Starbucks Iced Pumpkin Cream Shaken Espresso, Starbucks Iced Vanilla Protein Cream Shaken Espresso.
FAQ
Is Starbucks Iced Brown Sugar Oatmilk Shaken Espresso high in caffeine?
Yes, very. A Grande (16 fl oz) Starbucks Iced Brown Sugar Oatmilk Shaken Espresso has 255 mg, which is 2.7 times an 8 fl oz cup of brewed coffee (95 mg).
How much caffeine is in a Tall Starbucks Iced Brown Sugar Oatmilk Shaken Espresso?
A Tall (12 fl oz) Starbucks Iced Brown Sugar Oatmilk Shaken Espresso has 170 mg of caffeine, 85 mg less than a Grande (16 fl oz) Starbucks Iced Brown Sugar Oatmilk Shaken Espresso.
How much caffeine is in a Venti Starbucks Iced Brown Sugar Oatmilk Shaken Espresso?
A Venti (24 fl oz) Starbucks Iced Brown Sugar Oatmilk Shaken Espresso has 340 mg of caffeine, 85 mg more than a Grande (16 fl oz) Starbucks Iced Brown Sugar Oatmilk Shaken Espresso.
Can I drink Starbucks Iced Brown Sugar Oatmilk Shaken Espresso at night?
Not if you want to sleep well. Had at 7 pm, it leaves about 156 mg in an average adult at an 11 pm bedtime, above the 50 mg most people sleep fine with. The latest time for an 11 pm bedtime is about 10:45 am.
How long does the caffeine in Starbucks Iced Brown Sugar Oatmilk Shaken Espresso last?
It peaks about 75 minutes after you start it. Of the 255 mg, about 118 mg is still in you 6 hours later and 51 mg after 12 hours, for an average adult with a 5-hour half-life.
Does Starbucks Iced Brown Sugar Oatmilk Shaken Espresso have more caffeine than Red Bull?
Yes. A Grande (16 fl oz) Starbucks Iced Brown Sugar Oatmilk Shaken Espresso has 255 mg; an 8.4 fl oz can of Red Bull has 80 mg.
Method and limits
The caffeine figure comes from starbucks.com; recipes, brewing and batches vary, so a real serving can differ. The curves use a standard one-compartment model with an average 5-hour half-life and a sleep-friendly line of 50 mg; your own body may clear caffeine faster or slower. How it works has the details.
These are estimates for information, not medical advice. If you are pregnant, ask your doctor; common guidance is under 200 mg a day.
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