Source : Webster's Revised Unabridged Dictionary (1913)

Stum \Stum\, v. t. [imp. & p. p. {Stummed}; p. pr. & vb. n.
   {Stumming}.]
   To renew, as wine, by mixing must with it and raising a new
   fermentation.

         We stum our wines to renew their spirits. --Floyer.

Source : WordNet®

stumming
     See {stum}