Above, I have photographed three different methods of preparation of the Yaupon leaves. On the left, freshly cut terminal branches were placed into a conventional oven and allowed to roast at 330 F for fifteen minutes. On the right, product was slowly dried at 130 F for three hours in the food dehydrator. In the middle, leaf was allowed to enzymatically blacken at 130 F for one hour, and was then transferred into the oven at 330 F for fifteen minutes - leaf was black and limp, yet to become crisp. So the sample on the left, maillard reactions occur, and enzymes are heat-killed; product is much lighter in color, with green to brown colors, and is bitter. On the right Polyphenol Oxidase and other enzymes darken the leaf; product is more uniformly dark and lacks the bitterness of maillard roasts. The middle combines both processes and develops some red colors, and has some bitterness. The difference between top row and bottom is whole leaf, versus leaf crushed by hand.
Currently, I am brewing Yaupon Black Drink with a small espresso machine; the steam liberates readily soluble components. The hand-crushed leaf is first ground to a powder in a small coffee grinder mill. If the grind is too fine you will clog up the metal filter. Left behind on the filter are less soluble gummy residues. I use about 8 grams per cup of distilled water. The steam extraction is a much faster preparation method. Below is a picture of the cakes left behind after steam extraction. You can see all the above methods of preparations, light green to dark green, and also Dahoon Holly which is the the fibrous, loose cakes.