SToK Extra Bold cold brew carries more total caffeine per serving (170mg per 12 oz serving vs 155mg per 9.6 oz can), but ounce for ounce Starbucks canned Nitro (Black) is actually the stronger drink at about 16mg per fluid ounce against 14. Which one "has more caffeine" depends on whether you measure the container or the concentration.
Starbucks canned Nitro (Black) vs SToK Extra Bold cold brew: the numbers
| Starbucks canned Nitro (Black) | SToK Extra Bold cold brew | |
|---|---|---|
| Caffeine per serving | 155mg per 9.6 oz can | 170mg per 12 oz serving |
| Caffeine per fl oz | 16.1mg | 14.2mg |
| Servings to reach 400mg (FDA context) | 2.6 | 2.4 |
Sources: Starbucks canned Nitro (Black)'s figure is verified in our Starbucks canned Nitro (Black) caffeine guide against PepsiCo product facts (source); SToK Extra Bold cold brew's figure is verified in our SToK Extra Bold cold brew guide against SToK FAQ (source).
Which one should you pick?
Pick Starbucks canned Nitro (Black) when you want the lighter dose or a slower ramp, and SToK Extra Bold cold brew when you actually need the bigger hit and know your tolerance. If you are stacking either with other caffeinated drinks through the day, run the math against the 400mg reference rather than guessing.
For context, the FDA cites 400mg of caffeine a day as an amount generally not associated with negative effects in healthy adults. Tolerance and health vary, so treat these numbers as information, not advice.
Related reading
- Starbucks canned Nitro (Black): the full caffeine guide
- SToK Extra Bold cold brew: the full caffeine guide
- The verified caffeine database
FAQ
Does Starbucks canned Nitro (Black) or SToK Extra Bold cold brew have more caffeine? SToK Extra Bold cold brew: 170mg per 12 oz serving versus 155mg per 9.6 oz can for Starbucks canned Nitro (Black).
Which is stronger per ounce? Starbucks canned Nitro (Black), at about 16.1mg per fluid ounce versus 14.2mg for SToK Extra Bold cold brew.
Comparing caffeine? The caffeine comparison tool puts hundreds of drinks side by side, and the caffeine curfew calculator can check your cutoff time for tonight.