When a system is too complex it is hard to fully understand the underlying pieces. Why does Dayi, or other companies, use the recipe they use for their classic puerh cakes? Why do they add more lower leaf grades to some recipes and more higher leaf grades to other recipes? To answer these questions and begin to understand puerh we need to remove extraneous variables. Tasting different blended puerhs will only cause more confusion unless you can remove variables and focus on small changes. With the CPTR research cakes I saw a unique opportunity. I could remove many variables and focus solely on how leaf grade changed the tea. With these cakes the variables of region, farm, production method, tree age, processing methods, and post processing storage methods were all identical and therefore cancelled each other out. Focus can be given to the grade of leaf.