Reign Storm carries more total caffeine per serving (200mg per 12 oz can vs 140mg per 8 oz can), but ounce for ounce High Brew Double Espresso is actually the stronger drink at about 18mg per fluid ounce against 17. Which one "has more caffeine" depends on whether you measure the container or the concentration.
These are different categories of drink, which changes how the caffeine arrives. Energy drinks and sodas list an exact number because caffeine is a measured additive; brewed drinks vary with the beans and the brew, so their figures are compiled averages. The numbers here are the standard published values for each.
High Brew Double Espresso vs Reign Storm: the numbers
| High Brew Double Espresso | Reign Storm | |
|---|---|---|
| Caffeine per serving | 140mg per 8 oz can | 200mg per 12 oz can |
| Caffeine per fl oz | 17.5mg | 16.7mg |
| Servings to reach 400mg (FDA context) | 2.9 | 2.0 |
Sources: High Brew Double Espresso's figure is verified in our High Brew Double Espresso caffeine guide against Caffeine Informer (source); Reign Storm's figure is verified in our Reign Storm guide against Caffeine Informer (source).
Which one should you pick?
Pick High Brew Double Espresso when you want the lighter dose or a slower ramp, and Reign Storm 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
- High Brew Double Espresso: the full caffeine guide
- Reign Storm: the full caffeine guide
- The verified caffeine database
FAQ
Does High Brew Double Espresso or Reign Storm have more caffeine? Reign Storm: 200mg per 12 oz can versus 140mg per 8 oz can for High Brew Double Espresso.
Which is stronger per ounce? High Brew Double Espresso, at about 17.5mg per fluid ounce versus 16.7mg for Reign Storm.
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.