The Collaborative International Dictionary of English v.0.48:

Yeasty \Yeast"y\, a.
   Frothy; foamy; spumy, like yeast.
   [1913 Webster]

WordNet (r) 3.0 (2006):

yeasty
    adj 1: of or resembling or containing yeast [syn: yeasty,
           yeastlike]
    2: marked by spirited enjoyment [syn: zestful, yeasty,
       zesty, barmy]
    3: exuberantly creative

Moby Thesaurus II by Grady Ward, 1.0:

79 Moby Thesaurus words for "yeasty":
   agog, airy, aquiver, aroused, atingle, atwitter, barmy, bubbly,
   bursting, carried away, diastatic, dizzy, downy, ebullient,
   effervescent, enzymic, ethereal, excited, exhilarated,
   featherbrained, feathery, fermenting, fired, flighty, fluffy,
   foam-flecked, foamy, fribbling, frivolous, frothy, giddy,
   gossamery, harebrained, heady, high, hopped up, impassioned,
   imponderous, inflamed, keyed up, lathered up, lathery, leavening,
   leger, light, light as air, light-headed, lighter than vanity,
   manic, mousse, moved, raising, ready to burst, roused,
   scatterbrained, soapsuddy, soapsudsy, soapy, souffle, spumose,
   spumous, spumy, steamed up, stimulated, stirred, stirred up, suddy,
   sudsy, thrilled, tingling, tingly, turned-on, unheavy, volatile,
   weightless, whipped up, worked up, working, wrought up