fermentation

Any of many anaerobic biochemical reactions in which an enzyme (or several enzymes produced by a microorganism) catalyses the conversion of one substance into another; especially the conversion (using yeast) of sugars to alcohol or acetic a

A state of agitation or excitement; a ferment.

[T]he Grace that is then given to us is like a piece of Leven put into a lump of dough, and Faith and Repentance do in all the periods of our life put it into fermentation and activity.

The universal fusion of races, languages, and customs, which had gone on for four centuries under Roman rule, had produced a corresponding fusion of creeds, an universal fermentation of human thought and faith.