I have been using Champion Nutrition Chocolate for a while and am very happy with the taste and how easy it mixes.

To switch things up a bit I recently bought Optimum Nutrition Double Chocolate and Natural Vanilla. The double chocolate mixes almost as easy as the CN chocolate (just cold water and a spoon), but the Natural Vanilla never mixes very nice. It stays clumpy no matter what.

Could it be because it is natural, or did I maybe get a bad batch?