Alcohol Fermentation Experiment

• The experiment focuses on the fermentation of alcohol.

Fermentation Process

• Invertase Reaction converts sucrose and water into glucose and fructose.
• Fermentation by yeast converts glucose into ethanol and carbon dioxide.

Test for Carbon Dioxide

• Introducing gas from fermented liquid into lime water produces calcium carbonate.
• The chemical reaction is: Ca(OH)2 (aq.) + CO2 (g) → CaCO3 (s) + H2O (l).
• This reaction confirms the evolution of CO2 gas.

Distillation Process

• The temperature of the vapor after 1mL of distillate is 78-79°C.
• The temperature at the end of distillation is 85°C.

Test for Alcohol

• A combustion test involves the ignition of flame.
• An iodoform test produces a yellow precipitate.
• No ignition indicates less alcohol content.

Fermentation

• It is a metabolic process that converts carbohydrates into alcohol or organic acids with the help of microorganisms like bacteria, yeast, and fungi.
• Carbohydrates converted include sugars and starch.

Yeast

• Yeast is a fungus and a unicellular, eukaryotic organism
• It ferments sugar into alcohol and carbon dioxide.

Saccharomyces cerevisiae

• It is a widely used yeast species that ferments sugar into ethanol and carbon dioxide
• Commonly used in baking, brewing, and winemaking.

Enzyme

• It is a biological protein molecule that acts as a catalyst in biochemical reactions.
• Important enzymes in yeast during fermentation include zymase and maltase.

Zymase

• It is a complex of enzymes, including alcohol dehydrogenase and pyruvate decarboxylase
• It catalyzes the fermentation of sugar into alcohol and carbon dioxide.

Maltase

• It catalyzes the hydrolysis of maltose into glucose (two molecules).
• Maltose is a disaccharide from 2 glucose molecules linked together
• Maltase breaks maltose into glucose molecules, which are then metabolized by yeasts into energy and carbon dioxide.

Alcohol Synonyms

• The different synonyms for alcohol include ethanol, ethyl alcohol, wine spirit, hydrated oxide of ethyl, Spiritus vini rectificatus, ethyl hydrate, drinking alcohol, and grain alcohol.

By-products of Commercial Fermentation

• Carbon Dioxide: It results from metabolic activity and is used to carbonate the final product.
• Ethanol: It is the primary product of alcohol fermentation and is used in the production of alcoholic beverages, fuel, solvents, etc.
• Lactic Acid: It is common in fermented dairy products and contributes to tangy flavor and texture
• Acetic Acid: It is a by-product of Acetous fermentation where ethanol is converted to acetic acid by acetic acid bacteria, and it's the main component of vinegar and also acts as a food preservative, flavoring agent, and household cleaner.
• Carbonic Acid: It is produced when carbon dioxide dissolves in water, which contributes to the acidity of fermented beverages. Important in the carbonation process of soft drinks and sparkling water.
• Glycerol: It is produced by yeast during sugar to alcohol conversion and acts as a solvent, humectant, sweetener, and precursor in cosmetic and pharmaceutical production.

Alcohol Proof

• It is a scale to measure the strength/concentration of alcohol in a beverage.
• 1 proof equals 0.5% alcohol by volume.
• i.e, 50% alcohol by volume is 100 proof; 40% by volume is 80 proof
• Proof number equals twice the alcohol by volume percentage.

Alcoholic Beverages

• Scotch (Whiskey): Made from malted barley and water, it undergoes stages of malting barley, mashing to extract sugars, fermenting mash with yeast to create wash, distilling the wash in copper pot stills, and aging the distilled spirit in oak barrels for a minimum of 3 years
• Rye (Whiskey): Primarily from rye grain, its process includes mashing rye grains, fermenting mash with yeast, distilling liquid in copper stills, and aging in charred oak barrels for a minimum of 2 years.
• Bourbon: Primarily from corn (51%), along with rye, barley, and wheat, and the process includes mashing, fermenting with yeast, distilling, and aging for a minimum of 2 years.
• Rum: From sugarcane or its byproducts, it is made by fermenting byproducts or sugarcane with yeast, and distilling and aging in oak barrels.
• Vodka: Can be made from various ingredients (grains, potatoes, grapes) and involves fermenting raw material with yeast, distilling for purity, filtering through activated charcoal, diluting with water for desired alcohol content, and bottling the finished vodka.