acidulate

from WordNet (r) 3.0 (2006)

acidulate
    v 1: make sour or more sour [syn: {sour}, {acidify},
         {acidulate}, {acetify}] [ant: {dulcify}, {dulcorate},
         {edulcorate}, {sweeten}]

from The Collaborative International Dictionary of English v.0.48

Acidulate \A*cid"u*late\, v. t. [imp. & p. p. {Acidulated}; p.
   pr. & vb. n. {Acidulating}.] [Cf. F. aciduler. See
   {Acidulous}.]
   To make sour or acid in a moderate degree; to sour somewhat.
   --Arbuthnot.
   [1913 Webster]