The Collaborative International Dictionary of English v.0.48:

Varietal \Va*ri"e*tal\, a.
   Of or pertaining to a variety; characterizing a variety;
   constituting a variety, in distinction from an individual or
   species.
   [1913 Webster]

         Perplexed in determining what differences to consider
         as specific, and what as varietal.       --Darwin.
   [1913 Webster]

WordNet (r) 3.0 (2006):

varietal
    n 1: a wine made principally from one grape and carrying the
         name of that grape [syn: varietal, varietal wine] [ant:
         generic, generic wine]