I have written in this webspace before of my association with coffee; here seems as good a place as any to point out where. It should be no shock, then, to know that I note the appearance of coffee in the works I read--and it does appear in the books I read, certainly. I have identified it as a trope and a symbol in several of the popular novels I have read and written up at the behest of my freelance clientele, and I note that, in most cases, the protagonists of what I read take their coffee black.
A certain part of me wants to read affectively, using the insistence on black coffee as a means of fostering identity between the characters and me. Other parts of me know that 1) That is why the authors write their characters such, and it is good for book sales; and 2) I need not to read in such a way if I am to achieve the distance needed to do deeper reading. (The disjunction between the readerly tendency towards affect and the critical need to eschew it is part of the reason those of us who study literature are often thought to be dry and to have lost the love of what we do. For me, though, and at least, effective reading begins with affective reading; I use what provokes my emotional responses to guide my initial critical ventures. It works well enough.) I do a fair bit of the deeper reading, even for the general-consumption freelance pieces, including reading for how coffee is depicted (other than as a means to develop affect).
I have commented before, for example, that my taking my coffee black links me to my working-class background. Indeed, I learned to drink my coffee black--and it is a learned thing--on job sites, as going out into the Texas Hill Country on summer mornings did not reward taking along cream, but strong cups of coffee were of no small help in getting the work done. For me, therefore, there is a strong association between black coffee and hard work, and I have reason to think I am not the only one who makes the association. Those protagonists in the works I read who are coffee drinkers usually hail from working-class backgrounds. There are many of them, and they appear in no small number of bestselling novels. As such, I have to think that they are resonant with many readers, which would suggest that the idea of black coffee promoting hard work is widespread. There is something in the idealized person, the current iteration of the Emersonian Man (and, yes, I am aware of the problems embedded in that particular construct and phrasing, but that it is problematic does not mean it is not prevalent, and it would not be good to ignore it therefore), that asks for black coffee--even if it still serves as something of a crutch, an acknowledgment that the person alone does not suffice to the demands of the day.
I think I may have to come back to this idea tomorrow. I feel like I am onto something in some small, informal way.