leavening

leav·en·ing  (lv-nng)

n.

An agent that causes rising, fermentation, or ferment; leaven.

Thesaurus

Noun	1.	leavening - an influence that works subtly to lighten or modify something; "his sermons benefited from a leavening of humor" leaven imponderable - a factor whose effects cannot be accurately assessed; "human behavior depends on many imponderables"
	2.	leavening - a substance used to produce fermentation in dough or a liquid leaven substance - a particular kind or species of matter with uniform properties; "shigella is one of the most toxic substances known to man" baking powder - any of various powdered mixtures used in baking as a substitute for yeast sourdough - a leaven of dough in which fermentation is active; used by pioneers for making bread barm, yeast - a commercial leavening agent containing yeast cells; used to raise the dough in making bread and for fermenting beer or whiskey