What happens during fermentation process esp. in wines?
When grapes are smashed in the initial stage of wine making they are placed in an open end vat upended, Some small amount of yeast is added to start the fermenting process. There is also a natural white covering on the grape that also assists. The crushed grapes are stirred often as the fermenting begins( converting the sugar to alcohol ). Once the fermentation is almost completed the wine will be drawn and placed in a wine barrel. Here is will complete the fermentationThe bung hole will always be topped with wine so that impurities work their way out of the barrel. Once fermentation stops, the bung will be placed in the barrel sealing the contents until the bottling process starts.
C₆H₁₂O₆→2C₂H₅OH+2CO₂ The yeast enzymes turn glucose and fructose into ethanol and carbon dioxide. This continues until the alcohol reaches about 14% (or 18% if it’s a wine yeast), and then the alcohol kills the yeast. When the fermentation stops and the wine is bottled, the acids in the wine gradually react with some of the alcohol to form esters, which change the flavor of the wine from tangy to fruity.