The decomposition of foodstuffs generally accompanied by the evolution of gas is fermentation. This is a process by
fermentation process
which food or drink goes through a chemical change caused by enzymes produced from bacteria, microorganisms or yeasts. Fermentation alters the appearance and/or flavor of foods and beverages such as beer, buttermilk, cheese, vinegar, yogurt, liquor and wine. During fermentation organic matter is decomposed in the absence of air (oxygen); hence, there is always an accumulation of reduction products, or incomplete oxidation products. Some of these products are of importance to humans, and fermentation has therefore been used for their manufacture on an industrial scale.
Wine fermentation process
Wines owe much of their character to the fermenting process. Wine is an alcoholic beverage produced through the partial or total fermentation of grapes. Fermentation in wine making is simply the chemical change of natural grape sugar into roughly equal parts of ethyl alcohol and carbon dioxide gas. In alcoholic fermentation, sugar is
wine fermentation process
converted into alcohol and carbon dioxide. Alcoholic fermentation occurs when yeast cells convert carbohydrate sources to ethanol and carbon dioxide. Natural fermentation begins immediately after grapes are crushed. If one squeezes a bunch of ripe grapes in his hand and lets the juice fall into a container, the juice will ferment into a kind of wine.