Why can't I find a good quality puree in the supermarkets? I picked up a few online but everything I find in the stores tastes and feels so much more watery. Even the stuff that is supposedly 100% acai.

Do the super markets water their juices down?

It feels and tastes watered down because it is! Acai can't be stored and it doesn't last very long in the puree state that you want. What the larger stockists tend to do is to make the acai into a powder then reconstitute it with water.

This watered down version of acai can technically still be called 100% acai, but as you've noticed it is nothing like the purees you can get elsewhere.