Sobe Life Water Calories?

My buddy just gave me a "zero calorie" Sobe Life Water, Fuji Apple Pear. I checked the label before I drank it, and it says 0 calories.

However, after drinking it, I read more, and I see that it has 4 grams of carbohydrates per serving, and 2.5 servings per bottle, so I consumed 10 grams of carbs. If carbohydrates have 4 calories per gram, and I consumed 10 grams, how can this be 0 calories?