Source : Webster's Revised Unabridged Dictionary (1913)

Rack \Rack\, v. t. [Cf. OF. vin raqu['e] squeezed from the dregs
   of the grapes.]
   To draw off from the lees or sediment, as wine.

         It is in common practice to draw wine or beer from the
         lees (which we call racking), whereby it will clarify
         much the sooner.                         --Bacon.

   {Rack vintage}, wine cleansed and drawn from the lees.
      --Cowell.