GCSE Chemistry (AQA)

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Fermentation

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Organic chemistry Reactions of alkenes and alcohols

Fermentation

4:46 Alcohols: Structure, Formula, and Reactions
Spec 4.7.2.3
Previous Reactions of Alcohols Next Carboxylic Acid Names & Formulae
  • Ethanol is a widely used alcohol found in alcoholic drinks, perfumes, cosmetics, and fuels.
  • Alcohols are a type of organic compound with various uses.
  • Ethanol is commonly produced through fermentation, a respiration process without oxygen carried out by yeast cells.
  • In fermentation, yeast breaks sugars down into ethanol and carbon dioxide.
  • Yeast, a type of fungus, is placed in a fermentor for fermentation.
  • The reaction involves glucose breaking down into ethanol and carbon dioxide, releasing energy for yeast.
  • Sugar, specifically glucose, is added to the fermentor and stirred with yeast for fermentation.
  • Ethanol is tapped out from the bottom of the fermentor, while carbon dioxide escapes from the top.
  • Fermentation usually occurs in a sugar solution, typically sugar dissolved in water (aqueous solution).
  • Aqueous solutions of ethanol are produced when sugar solutions are fermented using yeast.
  • Ethanol dissolves into water during fermentation, and carbon dioxide bubbles form, making the surface foamy.
  • Ideal fermentation conditions include sugars dissolved in water, nutrients like vitamins, and an airlock to allow CO2 escape while preventing oxygen entry.
  • Oxygen presence can cause ethanol oxidation into ethanol acid (vinegar).
  • Fermentation requires a warm temperature between 25��C and 35��C for optimal reaction.
  • Controlling temperature is crucial; too cold slows the reaction, too warm deactivates yeast enzymes.
  • Recall all conditions needed for fermentation with yeast for exams.

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