" Cloves sweetened the breath and stoppered up the bowel. A drop of musk or ambergris was likely to inspire passions by firing the lower regions. Rosamund was a little hesitant with these last two lest she unleash something beyond anyone's control. Filip had chuckled when she confessed her fears to him and threatened to advertise these when the place opened.
The varieties of what could be added were endless, as was the transformation even a small sprinkle of something like vanilla or milk could lend the dark fluid. It changed from being a little bitter to luscious.
Likewise, a few extra twists with the molinillo and the consistency altered from gritty to frothy, to smooth as silk, leaving a fine coating on the tongue and throat that could be revisited for hours after. Including a small quantity of chili made the drink hot and spicy; cinnamon made it sweet and even heady. "

― Karen Brooks , The Chocolate Maker's Wife