Fermentation & Alcohol Production

What is fermentation? Fermentation is a process when microorganisms are grown on a large scale to obtain a useful product. Fermentation is the conversion of a carbohydrate such as sugar in to an acid or an alcohol. Fermentation tanks

The process Ethanol is made from fermentation. This converts sugar from sugar cane or sugar beet in to ethanol and carbon dioxide. Yeast contain enzymes that are natural catalysts for making this process happen. Yeast is added to a sugar solution and left for several days in the absence of air. These anaerobic conditions cause zymase enzymes in the yeast to convert the glucose in to ethanol and carbon dioxide. The optimum temperature for fermentation is 37°c as yeast grows best at this temperature. C₆H₁₂O₆ 2 CH₃CH₂OH + 2 CO₂ Chemical equation to symbolise conversion.

Some uses for alcohol Denatured alcohol- A toxic alcohol used as a fuel or solvent. Rubbing alcohol- A denatured alcohol used in topical applications. Propanol- Used to sterilize Alcoholic beverages- Any drink containing ethanol. Alcohol fuel- An alternative fuel

New ways of making ethanol Pure ethanol can also be produced by reacting ethene with steam. This process is called hydration. Ethene + steam ethanol C₂H₄(g)+ H₂O(g) C₂H₅OH(g) Ethene and steam are mixed together, and then passed continuously over a catalyst of phosphoric acid. The temperature needed for this reaction is 300°c.

Fractional Distillation The ethanol solution can be concentrated by fractional distillation to make products like whisky and brandy. Ethanol boils at 78°c, so when an ethanol- water mixture is heated, the ethanol boils at a lower temperature and is separated. The final liquid that distils over at 78°c is 96% pure ethanol. It is impossible to remove the final 4% of water by distillation.

Wine Fermentation The process of fermentation in wine is the catalyst function that turns grape juice in to an alcoholic beverage. Yeast interact with sugars in the juice to create ethanol and carbon dioxide. In wine making the temperature, speed of fermentation and the oxygen levels are important. It may be done in steel tanks or an open wooden vat.

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