Fermentation in
food processing typically refers to the conversion of
sugar to
alcohol using
yeast under
anaerobic conditions. A more general definition of fermentation is the chemical conversion of
carbohydrates into alcohols or
acids. When fermentation stops prior to complete conversion of sugar to alcohol, a
stuck fermentation is said to have occurred. The science of fermentation is known as
zymology.
Fermentation usually implies that the action of the microorganisms is desirable, and the process is used to produce alcoholic beverages such as wine, beer, and cider. Fermentation is also employed in preservation to create lactic acid in sour foods such as pickled cucumbers, kimchi and yogurt.
Since fruits ferment naturally, fermentation precedes human history. Since prehistoric times, however, humans have been controlling the fermentation process. The earliest evidence of winemaking dates from eight thousand years ago, in Georgia, in the Caucasus area.[1] Seven-thousand-year-old jars of wine have been excavated in the Zagros Mountains in Iran, which are now on display at the University of Pennsylvania.[2] There is strong evidence that people were fermenting beverages in Babylon circa 5000 BC,[3] ancient Egypt circa 3150 BC,[4] pre-Hispanic Mexico circa 2000 BC,[3] and Sudan circa 1500 BC.[5] There is also evidence of leavened bread in ancient Egypt circa 1500 BC[6] and of milk fermentation in Babylon circa 3000 BC.[3] The Chinese were probably the first to develop vegetable fermentation.[3]
"I am of the opinion that alcoholic fermentation never occurs without simultaneous organization, development and multiplication of cells.... If asked, in what consists the chemical act whereby the sugar is decomposed ... I am completely ignorant of it."
