To rank 15 Starbucks drinks, I taste-tested a variety of beverages from Frappuccinos to hot tea and from very sugary drinks to ones that were sugar-free. The number one criterion was to find ...

The most recent time I ordered the drink, I discovered just how much caffeine this small, eight-ounce coffee pack contained.

But labels don't have to reveal how much caffeine the products pack. We will. We measured the amount in 27 top-selling energy drinks and shots ... a 16-ounce Starbucks Grande, 330 milligrams.

Here's how Seattle's biggest coffee chain is capitalizing on our need for caffeine. There's a reason why Starbucks always ends ... and nuts, are low-cost add-ons that do eventually add up.