What is Fermentation? - Fermentation is the conversion of a carbohydrate such as sugar into an acid or an alcohol. More specifically, fermentation can refer to the use of yeast to change sugar into alcohol or the use of bacteria to create lactic acid in certain foods.

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Fermentation makes foods more nutritious, as well as delicious! - The Flavor, Nutrition, and Craft of Live-Culture Foods.

 Grape sugar is converted into alcohol and carbon dioxide by the action of yeast. For dry wines the process is allowed to continue until all the sugar has been converted into alcohol. Source. 

 What Is Fermentation? - Fermentation is the energy-yielding anaerobic metabolic breakdown of a nutrient molecule, such as glucose, without net oxidation. Fermentation yields lactate, acetic acid, ethanol, or some other simple product.

 Used in the process of preparing black and oolong tea, this step involves allowing the natural browning enzymes present in tea leaf to oxidize fresh green tea leaves and to impart the darker brown-red color and characteristic aroma. - Source 

This is the process of producing alcohol and carbon dioxide through the actions of yeast on grain-based sugars. Source

 Workers gather the tobacco leaves in large piles (bulk) after the harvest. The leaves are moistened and allowed to ferment. Temperatures may reach 140° inside the bulk before it is taken apart and restacked, temporarily halting the fermentation process. Source