At first blush, White Wave Food’s Stok black coffee shots look like any other 0.5 oz. creamer in a Bosch thermoformed cup. The foil lid even declares it to be a non-dairy coffee product that has undergone aseptic processing.

Closer scrutiny, however, reveals Stok to be an energy drink, the fastest growing category in the beverage category. The tiny cup packs 40 milligrams of pure caffeine, the equivalent of an ounce of espresso. “Limit 2/day,” the package disclaims. “Warning: high caffeine.”

The Dean Foods division introduced Stok two years ago at convenience store coffee services. The Broomfield, CO, firm describes Stok as “a powerful caffeine hit” that “delivers a pop of pure, invigorating caffeine.”

“There is no other product available today quite like this,” states Trevor Bynum, Stok marketing director. “Imagine being able to add a little get up and go to your coffee simply by adding a single serving of Stok.”

Sweet and unflavored versions exist. Both are intended as a supplement to black coffee, which accounts for 51 percent of consumption, according to the National Coffee Association.