What is the meaning of fermenting?

noun

• A process in which an agent causes an organic substance to break down into simpler substances; especially, the anaerobic breakdown of sugar into alcohol.
  • synonyms: zymosis, zymolysis, fermentation, ferment

verb

• Be in an agitated or excited state.
  • usage: "The Middle East is fermenting"; "Her mind ferments"
  • synonyms: ferment
• Work up into agitation or excitement.
  • usage: "Islam is fermenting Africa"
  • synonyms: ferment
• Cause to undergo fermentation.
  • usage: "We ferment the grapes for a very long time to achieve high alcohol content"; "The vintner worked the wine in big oak vats"
  • synonyms: ferment, work
• Go sour or spoil.
  • usage: "The milk has soured"; "The wine worked"; "The cream has turned-we have to throw it out"
  • synonyms: sour, turn, ferment, work