ferment vs leavening

ferment

noun
  • A gentle internal motion of the constituent parts of a fluid; fermentation. 

  • Something, such as a yeast or barm, that causes fermentation. 

  • A state of agitation or of turbulent change. 

  • A catalyst. 

verb
  • To stir up, agitate, cause unrest or excitement in. 

  • To react, using fermentation; especially to produce alcohol by aging or by allowing yeast to act on sugars; to brew. 

leavening

noun
  • The process by which something is leavened. 

  • Synonym of leavening agent 

adj
  • Making light by aeration. 

How often have the words ferment and leavening occurred in a corpus of books? (source: Google Ngram Viewer )