Doppio and Bulletproof Coffee 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 Bulletproof Coffee's differentiating factor?In following section we will take a close look at what is Doppio and Bulletproof Coffee color, serving style, types and much more. First thing to know is what are the different types of Doppio and Bulletproof Coffee. Well, Doppio types include Espresso while types of Bulletproof Coffee are Espresso.