Check your labels! Here's why: many commercial cranberry juices, will say 100% juice. That does NOT mean they're made with 100% cranberries. They use other sweeter fruit to balance the tart cranberries, which still makes it 100% juice. Cranberry cocktail, on the other hand, is typically all cranberry juice but with the added sugar (and possibly high fructose corn syrup). In addition, you can also buy unsweetened pure cranberry juice; however, it's incredibly tart. For this drink, it's recommended that you stick with sweetened 100% cranberry juice which isn't quite as tart as unsweetened pure cranberry juice but not as sweet as cranberry juice cocktail.