From WordNet (r) 3.0 (2006) [wn]:
fermenting
n 1: a process in which an agent causes an organic substance to
break down into simpler substances; especially, the
anaerobic breakdown of sugar into alcohol [syn: zymosis,
zymolysis, fermentation, fermenting, ferment]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Ferment \Fer*ment"\, v. t. [imp. & p. p. Fermented; p. pr. &
vb. n. Fermenting.] [L. fermentare, fermentatum: cf. F.
fermenter. See Ferment, n.]
To cause ferment or fermentation in; to set in motion; to
excite internal emotion in; to heat.
[1913 Webster]
Ye vigorous swains! while youth ferments your blood.
--Pope.
[1913 Webster]