The Collaborative International Dictionary of English v.0.48:

Caffetannic \Caf`fe*tan"nic\, a. [Caffeic + tannic.] (Chem.)
   Pertaining to, or derived from, the tannin of coffee.
   [1913 Webster]

   Caffetannic acid, a variety of tannin obtained from coffee
      berries, regarded as a glucoside.
      [1913 Webster]