Any suggestions to explain shifts in taste historically?  Recently I  
read Rod Phillips, A Short History of Wine, which emphasized shifts  
in taste (literally for wine).  Obviously, this is true for other  
alcoholic beverages  Think of the problems for Scotch whiskey in  
recent decades.  It is also true for many other of the consumables  
studied by ADHS.

A related topic is the problem of a glut in production or at least  
ability to produce, and the response of producers: sell more high  
quality, high price product to compensate for less volume.  This  
seems to be the case today for producers of coffee and tea and, for  
different reasons, tobacco.

I know less about illegal drugs.