Doppio and Earl Grey Tea are produced all around the globe. And they change according to region in where they are cultivated. So, the question arises what is Doppio and Earl Grey Tea's differentiating factor?In following section we will take a close look at what is Doppio and Earl Grey Tea color, serving style, types and much more. First thing to know is what are the different types of Doppio and Earl Grey Tea. Well, Doppio types include Espresso while types of Earl Grey Tea are Herbal.